Controlled release of drug from folate-decorated and graphene mediated drug delivery system: Synthesis,loading efficiency,and drug release response

A novel folate-decorated and graphene mediated drug delivery system was prepared that involves uniquely combining graphene oxide (GO) with anticancer drug for controlled drug release. The nanocarrier system was synthesized by attaching doxorubicin (DOX) to graphene oxide via strong π–π stacking interaction, followed by encapsulation of graphene oxide with folic acid conjugated chitosan. The π–π stacking interaction, simplified as a non-covalent type of functionalization, enables high drug loading and subsequent controlled release of the drug. The encapsulated graphene oxide enhanced the stability of the nanocarrier system in aqueous medium because of the hydrophilicity and cationic nature of chitosan. The loading and release of DOX indicated strong pH dependence and imply hydrogen-bonding interaction between graphene oxide and DOX. The proposed strategy is advantageous in terms of targeted drug delivery and has high potential to address the current challenges in drug delivery. Thus, the prepared nanohybrid system offers a novel formulation that combines the unique properties of a biodegradable material, chitosan, and graphene oxide for biomedical applications.     

Subcellular tracking of drug release from carbon nanotube vehicles in living cells

The direct observation of drug release from carbon nanotube vehicles in living cells is realized through a unique two-dye labeling approach. Single-walled carbon nanotubes (SWNTs) are firstly marked with fluorescein isothiocyanate (FITC) to track their location and movement inside the cell. Then a fluorescent anticancer drug doxorubicin (DOX) is attached by means of π-stacking onto SWNTs. Delivered by SWNTs into cells, DOX will detach from the vehicle in an acidic environment due to the pH-dependent π-π stacking interaction between DOX and SWNTs. From observation of the two different kinds of fluorescence (green and red) that respectively represent the carrier SWNTs and drug DOX, the process of drug release inside the living cell can be monitored under a confocal microscope. Results show that the drug DOX detaches from SWNTs inside the lysosomes to yield free molecules and escape into the cytoplasm and finally into the nucleus, while the vehicle SWNTs are trapped inside the lysosomes, without entering the nucleus. The current observations confirm previously proposed mechanisms for drug/DOX release inside cells. The experimental establishment of drug-release mechanisms in living cells here might provide important insights for future design of new drug-delivery and release systems.     

Highly Augmented Drug Loading and Stability of Micellar Nanocomplexes Composed of Doxorubicin and Poly(ethylene glycol)–Green Tea Catechin Conjugate for Cancer Therapy

Low drug loading and instability in blood circulation are two key challenges that impede the successful clinical translation of nanomedicine, as they result in only marginal therapeutic efficacy and toxic side effects associated with premature drug leakage, respectively. Herein, highly stable and ultrahigh drug loading micellar nanocomplexes (MNCs) based on the self‐assembly of the anticancer drug doxorubicin (DOX) and a poly(ethylene glycol)–epigallocatechin‐3‐O‐gallate (EGCG) conjugate are developed. The formation of these MNCs is facilitated by strong favorable intermolecular interactions between the structurally similar aromatic EGCG and DOX molecules, which impart exceptionally high drug‐loading capability of up to 88% and excellent thermodynamic and kinetic stability. Unlike two clinical formulations of DOX—free DOX and liposomal DOX, which are not effective below their lethal dosages, these DOX‐loaded MNCs demonstrate significant tumor growth inhibition in vivo on a human liver cancer xenograft mouse model with minimal unwanted toxicity. Overall, these MNCs can represent a safe and effective strategy to deliver DOX for cancer therapy.     

pH-Controlled Delivery of Doxorubicin to Cancer Cells, Based on Small Mesoporous Carbon Nanospheres

Mesoporous carbon nanospheres (MCNs) with small diameters of ≈90 nm are developed as an efficient transmembrane delivery vehicle of an anticancer drug, doxorubicin (DOX). MCNs exhibit a high loading capacity toward DOX due to hydrophobic interactions and the supramolecular π stacking between DOX and the carbonaceous structures, on which the pH-dependent drug release are successfully achieved. Specifically, DOX can be loaded onto MCNs in basic solution and in a physiological pH range, while release occurs in acidic solution in its ionized state. By effective passive and active targeting, MCNs can be readily internalized into HeLa cells, where the carried DOX can be efficiently released in the acidic microenvironment of the tumors for further therapy. The endocytosis and cytotoxicity of DOX@MCNs toward HeLa cells are investigated by confocal microscopy and MTT assay. This smart pH-dependent drug loading and release property of DOX@MCNs makes it possible to reduce the cytotoxicity to normal tissues during circulation in the body since the normal physiological pH is ≈7.4.     

Preparation and characterization of self-assemblied nanoparticles based on folic acid modified carboxymethyl chitosan

Folate (FA) modified carboxymethyl chitosan (FCC) has been synthesized and the hydrogel nanoparticles can be prepared after the sonication. Formation and characteristics of nanoparticles of FCC were studied by fluorescence spectroscopy and dynamic light scattering methods. The critical aggregation concentration value of FCC in water was 9.34 × 10⁻² mg/ml and the mean hydrodynamic diameter of particle was 267.8 nm. The morphology of nanoparticles was observed by transmission electron microscopy which had spherical shape. Loading capacity (LC), loading efficiency (LE) and the in vitro release profiles of nanoparticles were investigated by doxorubicin (DOX) as a model drug. When the initially added amount of DOX versus the constant amount of FCC polymer was increased, the LC in the nanoparticles was gradually increased and the LE decreased. The in vitro release profile of the DOX from the FCC nanoparticles exhibited sustained release. Cellular uptake of FCC nanoparticles was found to be higher than that of nanoparticles based on linoleic acid (LA) modified carboxymethyl chitosan because of the FA-receptor-mediated endocytosis, thereby providing higher cytotoxicity against Hela cells.     

Reduction-responsive drug delivery based on mesoporous silica nanoparticle core with crosslinked poly(acrylic acid) shell

A novel reduction-responsive drug delivery system was successfully constructed with mesoporous silica nanoparticle (MSN) core as a drug carrier and poly(acrylic acid) (PAA) shell crosslinked by disulfide linkages as a drug release switcher. To keep the pore structure of MSN intact, PAA was covalently attached to the exterior surface of MSN before removing structure-template via radical polymerization. After removing structure-template and loading doxorubicin (DOX), the PAA shell was crosslinked by cystamine dihydrochloride through amidation reaction. The loading content and the entrapment efficiency of DOX could reach up to 40.2% and 80.4%, respectively. Because that the dissociation of disulfide linkage is reduction-responsive, the release behavior of DOX could be controlled by varying the concentration of reductant, and the release rate was 49.4% after 24 h with the existence of 2 mM glutathione (simulated environment of cancer cells), about three times higher than that of without glutathione (corresponding to normal human cells), which was only 16.9%. The in vitro cell assays demonstrated that the disulfide linkages crosslinked MSN–PAA (MSN–PAA-crosslinked) was highly biocompatible and suitable to use as drug carrier, and the DOX loaded MSN–PAA-crosslinked showed remarkable cytotoxicity to HeLa cells (human cancer cells), and relatively lower cytotoxicity to 293 cells (human normal cells). These results imply that the MSN–PAA-crosslinked is a promising platform to construct reduction-responsive controlled drug delivery system for cancer therapy.     

Preparation and Optimization of Dry PLGA Nanoparticles by Spray Drying Technique

The aim of this article was to evaluate the potential of poly lactide-coglycolide (PLGA) nanoparticles (NPs) as carriers for controlling release of doxorubicin (DOX) via a spray drying technique. The challenge was to entrap a hydrophilic molecule into a lipophilic core molecule of PLGA. To achieve this objective, we modified conventional approach of drug loading to spray drying technique. The eight formulations of nanoparticles were prepared by modified double emulsion and solvent evaporation technique followed by spray drying using 2³ factorial designs. PLGA (A) and PVA (B) and stirring speed (C) were used as independent variables where particle size (Y₁), entrapment efficiency (Y₂) and percentage of drug release at the 32 hour (Y₃) were taken as dependant variables. The results showed that the method is easy and efficient for the entrapment of the drug as well as the formation of spherical nanoparticles. This modification improved DOX entrapment efficiency relative to controls real loadings up to 40%. The in vitro release studies indicated the DOX loaded PLGA nanoparticles provide controlled drug release over a period of 32 h. Hence, this investigation demonstrated the potential of the experimental design in understanding the effect of the formulation variables on the quality of DOX-PLGA nanoparticles.     

Doxorubicin loaded PVA coated iron oxide nanoparticles for targeted drug delivery

Magnetic drug targeting is a drug delivery system that can be used in locoregional cancer treatment. Coated magnetic particles, called carriers, are very useful for delivering chemotherapeutic drugs. Magnetic carriers were synthesized by coprecipitation of iron oxide followed by coating with polyvinyl alcohol (PVA). Characterization was carried out using X-ray diffraction, TEM, TGA, FTIR and VSM techniques. The magnetic core of the carriers was magnetite (Fe₃O₄), with average size of 10 nm. The room temperature VSM measurements showed that magnetic particles were superparamagnetic. The amount of PVA bound to the iron oxide nanoparticles were estimated by thermogravimetric analysis (TGA) and the attachment of PVA to the iron oxide nanoparticles was confirmed by FTIR analysis. Doxorubicin (DOX) drug loading and release profiles of PVA coated iron oxide nanoparticles showed that up to 45% of adsorbed drug was released in 80 h, the drug release followed the Fickian diffusion-controlled process. The binding of DOX to the PVA was confirmed by FTIR analysis. The present findings show that DOX loaded PVA coated iron oxide nanoparticles are promising for magnetically targeted drug delivery.     

Chondroitin/doxorubicin nanoparticulate polyelectrolyte complex for targeted delivery to HepG2 cells

Chondroitin (Chn) sulphate composed of N‐acetyl galactoseamine units was chosen to target doxorubicin (DOX) to asialoglycoprotein receptors (ASGPRs) overexpressed in HepG2 cells of hepatocellular carcinoma (HCC). Two different ways of targeting the drug to the receptors were compared with each other; (i) by polyelectrolyte complex formation of DOX and Chn (DC), (ii) by loading the drug in gelatin nanoparticles (NPs) and then coating them by Chn. The characteristics of DC complexes were determined by Fourier transform infrared spectroscopy, differential scanning calorimetry and CHN analysis. The complexes and Chn coated NPs were characterised for their particles size, zeta potential, drug loading and release efficiency. The morphology of NPs was studied by transmission electron microscopy. The cytotoxicity of DC complex and Chn coated NPs were compared on HepG₂ cells by MTT assay. The results showed that the cytotoxicity of both Chn coated gelatin NPs and DC complexes were significantly increased in comparison with free DOX. However, the presence of Chn did not have significant effect on the cytotoxicity of DOX loaded NPs. It was concluded that polyelectrolyte complex of DC could successfully target the drug to the hepatic ASGPRs and may be a simple promising way for targeted drug delivery in HCC.Inspec keywords: drug delivery systems, drugs, polymer electrolytes, electrokinetic effects, nanoparticles, particle size, cellular biophysics, nanocomposites, nanofabrication, molecular biophysics, cancer, gelatin, coatings, Fourier transform infrared spectra, differential scanning calorimetry, filled polymers, transmission electron microscopy, toxicology, nanomedicine, biomedical materialsOther keywords: chondroitin‐doxorubicin nanoparticulate polyelectrolyte complex, HepG2 cells, N‐acetyl galactoseamine units, chondroitin sulphate, asialoglycoprotein receptors, hepatocellular carcinoma, drug targeted delivery, receptors, polyelectrolyte complex formation, gelatin nanoparticles, DC complexes, Fourier transform infrared spectroscopy, differential scanning calorimetry, CHN analysis, Chn coated NPs, particle size, zeta potential, drug loading, drug release efficiency, morphology, transmission electron microscopy, cytotoxicity, MTT assay, hepatic ASGPRs     

Glycyrrhetinic acid-functionalized degradable micelles as liver-targeted drug carrier

Recently, many efforts have been devoted to investigating the application of functionalized micelles as targeted drug delivery carriers. In this study, glycyrrhetinic acid (GA, a liver targeting ligand) modified poly(ethylene glycol)-b-poly(γ-benzyl l-glutamate) micelles were prepared and evaluated as a potential liver-targeted drug carrier. The aggregation behavior, stability, size and morphology of the micelles were investigated. Anticancer drug doxorubicin (DOX) was encapsulated in the micelles. The drug release profile, in vivo distribution and the cytotoxicity against hepatic carcinoma QGY-7703 cells of DOX-loaded micelles were studied. The results indicated that the release profile was pH-dependent with Fickian diffusion kinetics. The micelles were remarkably targeted to the liver, inducing a 4.9-fold higher DOX concentration than that for free DOX·HCl. The DOX-loaded micelles exhibited almost twofold more potent cytotoxicity compared with DOX·HCl, and the cytotoxicity was time- and dosage-dependent. These results suggest that GA-functionalized micelles represent a promising carrier for drug delivery to the liver.     

Synthesis and characterization of gelatin nanoparticles using CDI/NHS as a non-toxic cross-linking system

Gelatin nanoparticles, cross-linked by a mixture of a water soluble carbodiimide (CDI) and N-hydroxysuccinimide (NHS) as a non-toxic cross-linking system, was prepared. The conventional two step desolvation method with acetone as the non-solvent was used. The mean size and size distribution as well as the morphology of the formed nanoparticles were evaluated and compared with those of nanoparticles cross-linked by glutaraldehyde (GA) as the most commonly used cross-linking agent. Furthermore, intrinsic viscosities of the nanoparticles cross-linked by CDI/NHS and GA were measured and compared under various conditions. The results showed the formation of smoother and more homogeneous nanoparticles with smaller size when CDI/NHS used as cross-linking agent under the same synthesis condition. Moreover, nanoparticles encapsulating paracetamol as a model drug were produced by the two different cross-linking agents and were characterized for drug entrapment and loading efficiencies and in vitro drug release. Both drug entrapment and loading efficiencies was higher in the CDI/NHS cross-linked nanoparticles; however, the release kinetics was comparable to that of nanoparticles cross-linked with GA. The differences in the characteristics of CDI/NHS and GA cross-linked nanoparticles were attributed to the different nature of network structures formed by the two cross-linking agents. On the whole, these results suggested that CDI/NHS cross-linked nanoparticles have high potential to be used for drug delivery application in preference to the nanoparticles synthesized by toxic cross-linking agents.     

以电纺丝蛋白纤维为模板的pH响应性介孔SiO2纳米管的制备及药物释放

以资源丰富的家蚕丝为原料,氯化钙/甲酸为溶解体系,利用静电纺丝法制得丝素蛋白（SF）纳米纤维;以SF纤维为模板在其表面涂覆SiO₂,经煅烧后获得了介孔SiO₂纳米管（MSNTs）;在MSNTs管壁上接枝醛基（-CHO）,利用醛基与盐酸阿霉素（DOXHCl）氨基之间的动态共价键制得了pH响应性药物释放体系。通过SEM、TEM、TG、比表面积（BET）分析、FTIR及紫外-可见吸收（UV-Vis）光谱对MSNTs的微观结构、功能化及载药体系的pH响应性进行了表征。结果表明:当SF浓度在15wt%~17wt%时,可获得圆柱状且直径在（113±27）~（134±32）nm范围内可调的SF纤维模板;通过调整涂覆液中十六烷基三甲基溴化铵（CTAB）的浓度来调节MSNTs管壁的厚度,当CTAB用量从1.25 mg/mL增加到3.75 mg/mL时,MSNTs管壁厚度从30~39 nm增加到63~65 nm,对应的比表面积从154 m2/g下降到98 m2/g,介孔平均孔径从12.5 nm下降到10.0 nm;醛基修饰的MSNTs载DOXHCl（MSNT-CHO-DOX）体系,在pH值分别为7.4、6.5和5.5的磷酸氢二钾-磷酸二氢钾（PB）缓冲溶液中进行释放,100 h时释药率分别达到23%、35%和75%,实现了MSNT-CHO-DOX载药体系的pH响应性释放。      

介孔生物玻璃/磷酸钙骨水泥多级孔复合支架的制备及其载药特性研究

采用离心法将介孔生物活性玻璃(MBG)和磷酸钙骨水泥(CPC)高效复合制备出介孔/大孔多级孔复合支架材料, 评价了其对抗癌药物阿霉素的装载及释放性能。实验结果表明, 采用离心法能在大孔支架CPC内有效负载大量的介孔生物活性玻璃, 使其比表面积高达100.1 m²/g, 负载量达47.2%, 而采用传统浸渍法则不能将MBG粉体材料负载于CPC支架上。载药实验发现离心法制备的介孔/大孔复合支架对阿霉素的装载量达到了46 mg/g, 是普通大孔CPC支架的11.5倍, 且在体外具有药物缓释的特性。     

Targeted anticancer prodrug with mesoporous silica nanoparticles as vehicles

A targeted anticancer prodrug system was fabricated with 180?nm mesoporous silica nanoparticles (MSNs) as carriers. The anticancer drug doxorubicin (DOX) was conjugated to the particles through an acid-sensitive carboxylic hydrazone linker which is cleavable under acidic conditions. Moreover, folic acid (FA) was covalently conjugated to the particle surface as the targeting ligand for folate receptors (FRs) overexpressed in some cancer cells. The in vitro release profiles of DOX from the MSN-based prodrug systems showed a strong dependence on the environmental pH values. The fluorescent dye FITC was incorporated in the MSNs so as to trace the cellular uptake on a fluorescence microscope. Cellular uptakes by HeLa, A549 and L929 cell lines were tested for FA-conjugated MSNs and plain MSNs respectively, and a much more efficient uptake by FR-positive cancer cells (HeLa) can be achieved by conjugation of folic acid onto the particles because of the folate-receptor-mediated endocytosis. The cytotoxicities for the FA-conjugated MSN prodrug, the plain MSN prodrug and free DOX against three cell lines were determined, and the result indicates that the FA-conjugated MSN prodrug exhibits higher cytotoxicity to FR-positive cells, and reduced cytotoxicity to FR-negative cells. Thus, with 180?nm MSNs as the carriers for the prodrug system, good drug loading, selective targeting and sustained release of drug molecules within targeted cancer cells can be realized. This study may provide useful insights for designing and improving the applicability of MSNs in targeted anticancer prodrug systems.     

Fabrication and evaluation of electrospun collagen/poly(N-isopropyl acrylamide)/chitosan mat as blood-contacting biomaterials for drug delivery

The recent advances in electrospinning have resulted in technologies facilitating easy drug entrapment, obtaining high surface area and thereby higher drug loading and release efficacy, burst control as well as the specific morphology which could be controlled according to the desired requirement. The present study focused on the fabrication of collagen/poly(N-isopropyl acrylamide)/chitosan complex with incorporated 5-fluorouracil, an anticancer drug by the method of electrospinning. The effect of chitosan on the fiber morphology and release kinetics was analyzed by varying its concentration. The release kinetics showed that the increase in chitosan concentration delayed the release of the drug from the fiber network. Nano hydroxyapatite was added to the fiber matrix in order to impart bioactivity, which was confirmed by studies in simulated body fluid. The addition of poly(N-isopropyl acrylamide) increased the blood compatibility of the prepared model. Thus, the model prepared to can find potential application in the field of cancer therapy as a drug-delivery agent in post-surgical treatment of cancer and as blood contacting biomaterial.     

Controlled drug delivery from porous hydroxyapatite grafts: An experimental and theoretical approach

Cylindrical hydroxyapatitic grafts at two different degree of porosity (60% and 40%) were tested as controlled drug delivery devices in order to evaluate the fundamental parameters which control release kinetics. The effect of device porosity, drug steric hindrance and drug loading on kinetics release has been appreciated using Ibuprofen-lysine and Hydrocortisone Na-succinate as non-steroidal and steroidal anti-inflammatory drug-models, respectively. The data put in evidence the difficulty for the more sterically hindered molecules to move throughout the microporosity of the ceramic graft. Furthermore, the results show how the higher drug load produces an initial higher release and how the less porous is the ceramic graft, the more evident is the initial burst release.A numerical approach, based on the use of the Finite Element Method, was adopted to describe the drug release kinetics from the porous ceramic graft. Numerical results on drug release in phosphate buffer saline solution were compared with experimental data and a good agreement was found. The importance of FEM modelling emerges as a predictive tool to study HA graft drug release performances in an efficient way, also in complex set-ups like the one here selected.     

A Multilayered Mesoporous Gold Nanoarchitecture for Ultraeffective Near-Infrared Light-Controlled Chemo/Photothermal Therapy for Cancer Guided by SERS Imaging

Surface-enhanced Raman scattering (SERS) imaging has emerged as a promising tool for guided cancer diagnosis and synergistic therapies, such as combined chemotherapy and photothermal therapy (chemo-PTT). Yet, existing therapeutic agents often suffer from low SERS sensitivity, insufficient photothermal conversion, or/and limited drug loading capacity. Herein, a multifunctional theragnostic nanoplatform consisting of mesoporous silica-coated gold nanostar with a cyclic Arg-Gly-Asp (RGD)-coated gold nanocluster shell (named RGD–pAS@AuNC) is reported that exhibits multiple “hot spots” for pronouncedly enhanced SERS signals and improved near-infrared (NIR)-induced photothermal conversion efficiency (85.5%), with a large capacity for high doxorubicin (DOX) loading efficiency (34.1%, named RGD/DOX–pAS@AuNC) and effective NIR-triggered DOX release. This nanoplatform shows excellent performance in xenograft tumor model of HeLa cell targeting, negligible cytotoxicity, and good stability both in vitro and in vivo. By SERS imaging, the optimal temporal distribution of injected RGD/DOX–pAS@AuNCs at the tumor site is identified for NIR-triggered local chemo-PTT toward the tumor, achieving ultraeffective therapy in tumor cells and tumor-bearing mouse model with 5 min of NIR irradiation (0.5 W cm⁻²). This work offers a promising approach to employing SERS imaging for effective noninvasive tumor treatment by on-site triggered chemo-PTT.     

介孔有机硅为载体的纳米递送系统制备及其体外化疗-光热联合治疗性能研究

有机/无机杂化的介孔有机硅纳米颗粒因其高的比表面积、丰富的介孔孔道、功能性的骨架以及高的药物装载量等特点而在生物医学领域受到广泛关注。本研究提出以二硫键桥接的有机/无机杂化介孔有机硅纳米颗粒为载体共装载化疗药物和光热剂, 设计制备以DNA分子作为控释“开关”修饰介孔有机硅纳米颗粒的纳米递送系统(ICG/DOX-MONs @DNA₂₀)。该纳米递送系统结合了光热剂的光热效应以及DNA分子随温度升高而从颗粒表面脱附的特性, 可实现近红外光照射激发药物在肿瘤细胞中的控制释放, 同时获得药物化疗-光热联合治疗肿瘤的效果。实验结果表明, 纳米递送系统在近红外光照下能迅速升温至43 ℃以上的热疗温度, 而且在37 ℃条件下6 h内仅缓慢释放药物12.3%, 而当温度升至43 ℃时则快速释放药物52.4%; 细胞实验显示该纳米递送系统能够被HeLa肿瘤细胞吞噬, 在近红外光照下有明显的药物化疗-光热联合治疗效果。因此, ICG/DOX-MONs@DNA₂₀纳米递送系统在药物化疗-光热联合治疗肿瘤方面具有应用前景。     

近红外荧光磁性复合载药脂质体的制备及应用

拟建立以近红外荧光磁性复合脂质体(NFMSLs)为模型药物载体、盐酸多柔比星(DOX)为包封药物的药物输送系统,研究了近红外荧光磁性载药复合脂质体(DOX-NFMSLs)的制备、性质及初步应用.采用共沉淀法制备FeO4磁流体,CdTe掺杂Se制备近红外量子点CdSeTe,薄膜分散法制备DOX-NFMSLs.用DOX荧光分光光度法测定DOX-NFMSLs的包封率和体外药物释放率;用DOX-NFMSLs与HepG2肝癌细胞共孵育来进行细胞成像和细胞毒性实验.结果表明,近红外CdSeTe量子点粒径约为5nm,闪锌矿结构,发射波长824 nm.磷脂与胆固醇质量比为8∶1,药脂比为1∶20的DOX-NFMSLs平均粒径为252.9 nm,Zeta电位为-48.6 mV,理想释放药物温度为41℃,平均包封率为(74.84±0.89)％.DOX-NFMSLs对HepG2肝癌细胞有一定的抗癌效果.得到了具有良好磁响应、释药温度T=41℃、可近红外成像的载药脂质体.     

In vitro evaluation of a novel pH sensitive drug delivery system based cockle shell-derived aragonite nanoparticles against osteosarcoma

ABSTRACT

Background: Osteosarcoma (OS) is a highly malignant primary bone cancer. Severe side effects and multidrug resistance are obstacles faced with chemotherapy against OS. With the hope to overcome the obstacles of the conventional chemotherapy, various targeted drug delivery systems using nanotechnology have been explored in the past few decades. Biogenic calcium carbonate (CaCO₃) has great potential to be a smart drug delivery system.

Results: In this study, cockle shells-derived aragonite nanoparticles (ANPs) were developed and loaded with doxorubicin (DOX). The physicochemical properties of the DOX-loaded ANPs (DOX-ANPs) were characterised by various techniques. The results of drug-loading study demonstrated that DOX was loaded onto ANPs at high loading and encapsulation efficiency (11.09% and 99.58%, respectively). The pH-sensitive release of DOX from DOX-ANPs was successful. At lower pH values (4.8), the release of DOX was much quicker than that at pH 7.4. Additionally, cellular uptake study using fluorescence microscopy showed obviously cellular uptake of DOX-ANPs through endocytosis. Moreover, the flow cytometric analysis revealed DOX-ANPs-induced cell cycle arrest, which was consistent with the mechanism of DOX. DOX-ANPs also showed an efficient cytotoxicity against OS cancer cells, close to the toxicity effect of free DOX at the same concentration. Morphological observations showed microvilli disappearance, chromatin condensation, cell shrinkage, membrane blebbing, and formation of apoptotic bodies, which confirmed both DOX-ANPs- and DOX-induced apoptosis of OS cancer cells in vitro.

Conclusion: Our findings indicated that ANPs could act as a pH-sensitive drug delivery against OS.