Eco-friendly chitosan microspheres as a novel one-step sorbent for the rapid purification and determination of pesticides and veterinary drug multi-residues in aquatic products with HPLC-MS/MS.

A modified QuEChERS method was developed to determine multi-class pesticide and veterinary residues in aquatic products. Chitosan microspheres were conveniently synthesized and utilized as the cleanup adsorbent in the QuEChERS procedure, showcasing rapid filtration one-step pretreatment ability for the determination of drug multi-residues in aquatic products. Compared to conventional synthetic sorbents, chitosan microspheres not only have good purification performance, but also have renewable and degradable properties. This novel sorbent worked well in the simultaneous determination of 95 pesticides and veterinary drug residues in aquatic products after being combined with an improved one-step vortex oscillating cleanup method. We achieved recoveries ranging from 64.0% to 115.9% for target drugs in shrimp and fish matrix. The limits of detection and quantification were 0.5-1.0 and 1.0-2.0 µg kg-1, respectively. Notably, hydrocortisone was detected with considerable frequency and concentration in the tested samples, underscoring the necessity for stringent monitoring of this compound in aquatic products.

Sustained release of stem cell secretome from nano-villi chitosan microspheres for effective treatment of atopic dermatitis.

Canine atopic dermatitis (AD) arises from hypersensitive immune reactions. AD symptoms entail severe pruritus and skin inflammation, with frequent relapses. Consequently, AD patients require continuous management, imposing financial burdens and mental fatigue on pet owners. In this study, we aimed to investigate the therapeutic relevance of secretome from canine adipose tissue-derived mesenchymal stem cells (MSCs), especially after encapsulation in nano-villi chitosan microspheres (CS-MS) to expect improved efficacy. Conditioned media (CM) from MSCs significantly inhibited the proliferation of splenocytes, induced the generation of regulatory T cells, and decreased mast cell degranulation. We found that beneficial soluble factors known to reduce AD symptoms, including transforming growth factor-beta 1, were detectable after sequential concentration and lyophilization of CM. The CS-MS, developed by a phase inversion regeneration method, showed high loading and sustained release of the secretome. Local injection of secretome-loaded CS-MS (ST/SC-MS) effectively reduced clinical severity compared to groups treated with secretome. Histological analysis revealed that ST/SC-MS potently suppressed epidermal hyperplasia, immunocyte infiltration and mast cell activation in the lesion. Taken together, this study presents a novel therapeutic approach exhibiting more potent and prolonged immunoregulatory efficacy of MSC secretome for canine AD treatment.

99mTc-labeled, tofacitinib citrate encapsulated chitosan microspheres loaded in situ gel formulations for intra-articular treatment of rheumatoid arthritis.

Inflammatory diseases including rheumatoid arthritis are major health problems. Although different techniques and drugs are clinically available for the diagnosis and therapy of the disease, novel approaches regarding radiolabeled drug delivery systems are researched. Hence, in the present study, it was aimed to design, prepare, and characterize 99mTc-radiolabeled and tofacitinib citrate-encapsulated microsphere loaded poloxamer in situ gel formulations for the intra-articular treatment. Among nine different microsphere formulations, MS/TOFA-9 was chosen as the most proper one due to particle size, high encapsulation efficiency, and in vitro drug release behavior. Poloxamer 338 at a concentration of 15% was used to prepare in situ gel formulations. For intra-articular administration, microspheres were dispersed in an in situ gel containing 15% Poloxamer 338 and characterized in terms of gelation temperature, viscosity, rheological, mechanical, and spreadability properties. After the determination of the safe dose for MS/TOFA-9 and PLX-MS/TOFA-9 as 40 µL/mL in the cell culture study performed on healthy cells, the high anti-inflammatory effects were due to significant cellular inhibition of fibroblasts. In the radiolabeling studies with 99mTc, the optimum radiolabeling condition was determined as 200 ppm SnCl2 and 0.5 mg ascorbic acid, and both 99mTc-MS/TOFA-9 and 99mTc-PLX-MS/TOFA-9 exhibited high cellular binding capacity. In conclusion, although further in vivo experiments are required, PLX-MS/TOFA-9 was found to be a promising agent for intra-articular injection in rheumatoid arthritis.

Ozonated Sunflower Oil Embedded within Spray-Dried Chitosan Microspheres Cross-Linked with Azelaic Acid as a Multicomponent Solid Form for Broad-Spectrum and Long-Lasting Antimicrobial Activity.

Multicomponent solid forms for the combined delivery of antimicrobials can improve formulation performance, especially for poorly soluble drugs, by enabling the modified release of the active ingredients to better meet therapeutic needs. Chitosan microspheres incorporating ozonated sunflower oil were prepared by a spray-drying method and using azelaic acid as a biocompatible cross-linker to improve the long time frame. Two methods were used to incorporate ozonated oil into microspheres during the atomization process: one based on the use of a surfactant to emulsify the oil and another using mesoporous silica as an oil absorbent. The encapsulation efficiency of the ozonated oil was evaluated by measuring the peroxide value in the microspheres, which showed an efficiency of 75.5-82.1%. The morphological aspects; particle size distribution; zeta potential; swelling; degradation time; and thermal, crystallographic and spectroscopic properties of the microspheres were analyzed. Azelaic acid release and peroxide formation over time were followed in in vitro analyses, which showed that ozonated oil embedded within chitosan microspheres cross-linked with azelaic acid is a valid system to obtain a sustained release of antimicrobials. In vitro tests showed that the microspheres exhibit synergistic antimicrobial activity against P. aeruginosa, E. coli, S. aureus, C. albicans and A. brasiliensis. This makes them ideal for use in the development of biomedical devices that require broad-spectrum and prolonged antimicrobial activity.

p75NTR antibody-conjugated microspheres: an approach to guided tissue regeneration by selective recruitment of endogenous periodontal ligament cells.

Repairing defects in alveolar bone is essential for regenerating periodontal tissue, but it is a formidable challenge. One promising therapeutic approach involves using a strategy that specifically recruits periodontal ligament cells (PDLCs) with high regenerative potential to achieve in situ regeneration of alveolar bone. In this study, we have created a new type of microsphere conjugated with an antibody to target p75 neurotrophin receptor (p75NTR), which is made of nano-hydroxyapatite (nHA) and chitosan (CS). The goal of this design is to attract p75NTR+hPDLCs selectively and promote osteogenesis. In vitro experiments demonstrated that the antibody-conjugated microspheres attracted significantly more PDLCs compared to non-conjugated microspheres. Incorporating nHA not only enhances cell adhesion and proliferation on the surface of the microsphere but also augments its osteoinductive properties. Microspheres effectively recruited p75NTR+ cells at bone defect sites in SD rats, as observed through immunofluorescent staining of p75NTR antibodies. This p75NTR antibody-conjugated nHA/CS microsphere presents a promising approach for selectively recruiting cells and repairing bone defects.

Preparation of pH-responsive chitosan microspheres containing aminopeptidase and their application in accelerating cheese ripening.

Microencapsulated enzymes have been found to effectively accelerate cheese ripening. However, microencapsulated enzyme release is difficult to control, often resulting in enzyme release during cheese processing and causing texture and flavor defects. This study aims to address this issue by developing aminopeptidase-loaded pH-responsive chitosan microspheres (A-CM) for precise enzyme release during cheese ripening. An aminopeptidase with an isoelectric point (pH 5.4) close to the pH value of cheese ripening was loaded on chitosan microspheres through electrostatic interaction. Turbidity titration measurements revealed that pH 6.5 was optimal for binding aminopeptidase and microspheres, affording the highest loading efficiency of 58.16%. Various characterization techniques, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy confirmed the successful loading of aminopeptidase molecules on the chitosan microspheres. In vitro release experiments conducted during simulated cheese production demonstrated that aminopeptidase release from A-CM was pH responsive. The microspheres retained the enzyme during the coagulation and cheddaring processes (pH 5.5-6.5) and only released it after entering the cheese-ripening stage (pH 5.0-5.5). By loading aminopeptidase on chitosan microspheres, the loss rate of the enzyme in cheese whey was reduced by approximately 79%. Furthermore, compared with cheese without aminopeptidase and cheese with aminopeptidase added directly, the cheeses made with A-CM exhibited the highest proteolysis level and received superior sensory ratings for taste and smell. The content of key aroma substances, such as 2/3-methylbutanal and ethyl butyrate, in cheese with A-CM was more than 15 times higher than the others. This study provides an approach for accelerating cheese ripening through the use of microencapsulated enzymes.

Berberine hydrochloride-loaded dung beetle chitosan/sodium alginate microspheres ameliorate DSS-induced colitis and regulate gut microorganisms in mice.

Berberine hydrochloride (BH) has long been known for its therapeutic efficacy. In the present study, we aimed to treat mice with colitis using dung beetle chitosan (DCS) -transported BH. To achieve this, BH-loaded DCS/sodium alginate microspheres (SA-DCS-BH) were prepared. The SA-DCS-BH was characterized using SEM, DLS, FT-IR, and XRD, then was used for administration and anti-inflammatory examination in mice. SEM and DLS confirmed the surface morphology of the microspheres, and the particle size was relatively uniform. FT-IR and XRD results confirmed that BH was successfully loaded. In vitro and in vivo studies showed that SA-DCS-BH had slow-release ability. After treatment with SA-DCS-BH, DAI was significantly reduced, colon weight and length increased, spleen length and weight reduced, concentrations of pro-inflammatory cytokines in colonic tissues were reduced, and gut microbiota species abundance was modulated. In addition, this study found a correlation between specific microbes and colitis indicators, Muribaculaceae showed sequential growth after receiving BH, SA-CS-BH, and SA-DCS-BH treatments, respectively. It was concluded that SA-DCS-BH effectively delivered the BH to the intestine with slow-release ability and exhibited anti-inflammatory effects by immune response. Compared to commercial chitosan, DCS has potential for modulating intestinal microorganisms and more suitable carrier for intestinal drug delivery systems.

In situ forming alginate/gelatin hydrogel scaffold through Schiff base reaction embedded with curcumin-loaded chitosan microspheres for bone tissue regeneration.

In this study, we developed a biocompatible composite hydrogel that incorporates microspheres. This was achieved using a Schiff base reaction, which combines the amino and aldehyde groups present in gelatin (Gel) and oxidized alginate (OAlg). We suggest this hydrogel as a promising scaffold for bone tissue regeneration. To further boost its osteogenic capabilities and mechanical resilience, we synthesized curcumin (Cur)-loaded chitosan microspheres (CMs) and integrated them into the Gel-OAlg matrix. This formed a robust composite gel framework. We conducted comprehensive evaluations of various properties, including gelation time, morphology, compressive strength, rheological behavior, texture, swelling rate, in vitro degradation, and release patterns. A remarkable observation was that the inclusion of 30 mg/mL Cur-CMs significantly enhanced the hydrogel's mechanical and bioactive features. Over three weeks, the Gel-OAlg/Cur-CMs (30) composite showed a cumulative curcumin release of 35.57%. This was notably lower than that observed in standalone CMs and Gel-OAlg hydrogels. Additionally, the Gel-OAlg/Cur-CMs (30) hydrogel presented a reduced swelling rate and weight loss relative to hydrogels devoid of Cur-CMs. On the cellular front, the Gel-OAlg/Cur-CMs (30) hydrogel showcased superior biocompatibility. It also displayed increased calcium deposition, alkaline phosphatase (ALP) activity, and elevated osteogenic gene expression in human bone marrow mesenchymal stem cells (hBMSCs). These results solidify its potential as a scaffold for bone tissue regeneration.

Preparation, Structural Characterization, and Enzymatic Properties of Alginate Lyase Immobilized on Magnetic Chitosan Microspheres.

Alginate lyase is an enzyme that catalyses the hydrolysis of alginate into alginate oligoalginates. To enhance enzyme stability and recovery, a facile strategy for alginate lyase immobilization was developed. Novel magnetic chitosan microspheres were synthesized and used as carriers to immobilize alginate lyase. The immobilization of alginate lyase on magnetic chitosan microspheres was successful, as proven by Fourier transform infrared spectroscopy and X-ray diffraction spectra. Enzyme immobilization exhibited the best performance at an MCM dosage of 1.5 g/L, adsorption time of 2.0 h, glutaraldehyde concentration of 0.2%, and immobilization time of 2.0 h. The optimal pH of the free alginate lyase was 7.5, and this pH value was shifted to 8.0 after immobilization. No difference was observed at the optimal temperature (45 °C) for the immobilized and free enzymes. The immobilized alginate lyase displayed better thermal stability than the free alginate lyase. The Km values of the free and immobilized enzymes were 0.05 mol/L and 0.09 mol/L, respectively. The immobilized alginate lyase retained 72% of its original activity after 10 batch reactions. This strategy was found to be a promising method for immobilizing alginate lyase.

Novel poly (N-methacryloyl-L-alanine acid) grafted chitosan microspheres based solid-phase extraction coupled with ICP-MS for simultaneous detection of trace metal elements in food.

Poly (N-methacryloyl-L-alanine acid) grafted tartaric acid-crosslinked chitosan microspheres (PNMA-TACS) were successfully synthesized and employed as a novel adsorbent for the separation and enrichment of metal ions in the food system. PNMA-TACS microspheres-based solid phase extraction (SPE) was coupled with ICP-MS for accurate quantification of trace V(V), Cr(III), As(III), Pb(II), Cd(II) and Cu(II). The obtained PNMA-TACS microspheres were characterized, and parameters influencing the method were optimized. Under optimal conditions, the calibration curves for Cu(II) and V(V) were linear within 0.01-30 µg L-1, the linear ranges of Cr(III), As(III), Pb(II) and Cd(II) were 0.01-15 µg L-1, and the detection limit of the developed approach was 1.1-3.7 ng L-1. The results were consistent with the consensus values of method validation implemented by two standards. Moreover, standard addition recovery experiments were performed in rice and milk powder, which achieved satisfactory recovery of 86.1-103.5%.

Enzymatic time-temperature indicator with cysteine-loaded chitosan microspheres/silver nanoparticles.

A time-temperature indicator (TTI) based on acid-base reaction was developed by applying a new pH dye composed of cysteine-loaded chitosan (Cys-CS) microspheres and silver nanoparticles (AgNPs). It was hypothesized that cysteine released by the disintegration of Cys-CS microspheres at a critical pH would cause AgNPs to aggregate, leading to color change. Cys-CS microspheres were produced as water-in-oil (paraffin oil, MCT oil, soybean oil) emulsions according to the KOH addition method. An enzymatic TTI was made using glucose oxidase, glucose, and catalase. Only paraffin oil produced Cys-CS microspheres (average diameter, 335 ± 100 µm), whereas the others did not, probably due to saponification with KOH. FTIR analysis confirmed that cysteine was encapsulated in the microspheres. The microspheres disintegrated at pH 6.18 in a titration test. The TTI pH gradually decreased and showed a sudden color change at pH 6.10, which was similar to the critical pH of microsphere disintegration.

Chitosan microspheres-based controlled-release nitrogen fertilizers improve the biological characteristics of Brassica rapa ssp. pekinensis and the soil.

Present study investigates the impact of chitosan microspheres-based controlled-release nitrogen fertilizer (Cm-CRNFs) on biological characteristics of Brassica rapa ssp. pekinensis (Chinese cabbage) and soil. The study was carried out under various four treatments, urea (0.8033 g), blank chitosan microspheres (without urea), Cm-CRNFs (0.8033 g), and a control group (CK). The results indicated that Cm-CRNFs significantly prolonged the nitrogen release and enhanced the plant shoot length, shoot diameter, number of branches, pods, total amino acids, and vitamin C of Brassica rapa ssp. pekinensis as well as increased the soil nutrient availability. Chao index of bacterial diversity analysis showed a significant reduction of 15.89 % in Cm-CRNFs, but the Shannon index value in Cm-CRNFs was increased by 23.55 % compared to CK. Furthermore, Cm-CRNFs treatment significantly influenced genus richness level of Arthrobacter, Archangium, Bacillus, and Flavihumibacter. Moreover, relative abundance of bacteria significantly enhanced Cm-CRNFs, including Acidobacteriota, Acitinobacteriota, Cloroflexi, Cyanobacteria, and Patescibacteria. Soil enzyme activity such as: urease, acid phosphatase, and catalase enzymes in Cm-CRNFs and urea treatment significantly increased. Besides, other enzymes such as: cellulase and ß-glucosidase activity decreased in the Cm-CRNFs treatment. It was concluded that Cm-CRNFs potentially prolonged discharge of micro/macronutrients and improved soil bacterial diversity, which ultimately enhanced the soil fertility and improved the soil enzyme activity.

Ink Based on the Tunable Swollen Microsphere for a 3D Printing Hydrogel with Broad-Range Mechanical Properties.

The development of the effective 3D printing strategy for diverse functional monomers is still challenging. Moreover, the conventional 3D printing hydrogels are usually soft and fragile due to the lack of an energy dissipation mechanism. Herein, a microsphere mediating ink preparation strategy is developed to provide tailored rheological behavior for various monomer direct ink writings. The chitosan microspheres are used as an exemplary material due to their tunable swelling ratio under the acid-drived electrostatic repulsion of the protonated amino groups. The rheological behaviors of the swollen chitosan microsphere (SCM) are independent on the monomer types, and various functional secondary polymers could be carried at a wide loading ratio by the acid driving. The SCM reinforces the hydrogel as the sacrificial bonds. With the adjustable composition, the 3D printing hydrogel mechanical properties are tunable in wide windows: strength (0.4-1.01 MPa), dissipated energy (0.11-3.25 MJ m-3), and elongation at break (47-626%). With the excellent printing and mechanical properties, the SCM inks enable multi-functional integration for soft device production, such as 4D printing robots and wearable strain sensors. We anticipate that this microsphere mediating 3D printing strategy can inspire new possibilities for the design of the robust hydrogels with a broad range of functionalities and mechanical performances.

Isotherm, Thermodynamics, and Kinetics of Methyl Orange Adsorption onto Magnetic Resin of Chitosan Microspheres.

Severe environmental pollution problems arising from toxic dyestuffs (e.g., methyl orange) are receiving increasing attention. Therefore, dyes' safe removal has become a research hotspot. Among the many physical-chemical removal techniques, adsorption using renewable biological resources has proved to be more advantageous over others due to its effectiveness and economy. Chitosan is a natural, renewable biopolymer obtained by deactivated chitin. Thus, the magnetic resin of chitosan microspheres (MRCM), prepared by reversed-phase suspension cross-linking polymerization, was used to remove methyl orange from a solution in a batch adsorption system. The main results are as follows: (1) The results of physical and swelling properties of MRCM indicated that MRCM was a type of black spherical, porous, water-absorbing, and weak alkali exchange resin, and it had the ability to adsorb methyl orange when it was applied in solutions above pH 2.0. (2) In batch adsorption studies, the maximum adsorption capacity was obtained at pH 5; the adsorption equilibrium time was 140 min; and the maximum adsorption was reached at 450 mg/L initial concentration. (3) Among the three isotherm adsorption models, Langmuir achieved the best fit for the adsorption of methyl orange onto MRCM. (4) The adsorption thermodynamics indicated that the adsorption was spontaneous, with increasing enthalpy, and was driven by the entropy. (5) The pseudo-second-order kinetics equation was most suitable to describe the adsorption kinetics, and the adsorption kinetics was also controlled by the liquid-film diffusion dynamics. Consequently, MRCM with relatively higher methyl orange adsorption exhibited the great efficiency for methyl orange removal as an environment-friendly sorbent. Thus, the findings are useful for methyl orange pollution control in real-life wastewater treatment applications.

Injectable, Anti-Cancer Drug-Eluted Chitosan Microspheres against Osteosarcoma.

The purpose of this study is to fabricate different anti-cancer drug-eluted chitosan microspheres for combination therapy of osteosarcoma. In this study, electrospray in combination with ground liquid nitrogen was utilized to manufacture the microspheres. The size of obtained chitosan microspheres was uniform, and the average diameter was 532 µm. The model drug release rate and biodegradation rate of chitosan microspheres could be controlled by the glutaraldehyde vapor crosslinking time. Then the 5-fluorouracil (5-FU), paclitaxel (PTX), and Cis-dichlorodiammine-platinum (CDDP) eluted chitosan microspheres were prepared, and two osteosarcoma cell lines, namely, HOS and MG-63, were selected as cell models for in vitro demonstration. We found the 5-FU microspheres, PTX microspheres, and CDDP microspheres could significantly inhibit the growth and migration of both HOS and MG-63 cells. The apoptosis of both cells treated with 5-FU microspheres, PTX microspheres, and CDDP microspheres was significantly increased compared to the counterparts of control and blank groups. The anti-cancer drug-eluted chitosan microspheres show great potential for the treatment of osteosarcoma.

A sustained release of BMP2 in urine-derived stem cells enhances the osteogenic differentiation and the potential of bone regeneration.

Cell-based tissue engineering is one of the optimistic approaches to replace current treatments for bone defects. Urine-derived stem cells (USCs) are obtained non-invasively and become one of the promising seed cells for bone regeneration. An injectable BMP2-releasing chitosan microspheres/type I collagen hydrogel (BMP2-CSM/Col I hydrogel) was fabricated. USCs proliferated in a time-dependent fashion, spread with good extension and interconnected with each other in different hydrogels both for 2D and 3D models. BMP2 was released in a sustained mode for more than 28 days. Sustained-released BMP2 increased the ALP activities and mineral depositions of USCs in 2D culture, and enhanced the expression of osteogenic genes and proteins in 3D culture. In vivo, the mixture of USCs and BMP2-CSM/Col I hydrogels effectively enhanced bone regeneration, and the ratio of new bone volume to total bone volume was 38% after 8 weeks of implantation. Our results suggested that BMP2-CSM/Col I hydrogels promoted osteogenic differentiation of USCs in 2D and 3D culture in vitro and USCs provided a promising cell source for bone tissue engineering in vivo. As such, USCs-seeded hydrogel scaffolds are regarded as an alternative approach in the repair of bone defects.

Radiometal-Labeled Chitosan Microspheres as Transarterial Radioembolization Agents against Hepatocellular Carcinoma.

Transarterial radioembolization (TARE) is an emerging treatment for patients with unresectable hepatocellular carcinoma (HCC). This study successfully developed radiometal-labeled chitosan microspheres (111In/177Lu-DTPA-CMS) with a diameter of 36.5 ± 5.3 µm for TARE. The radiochemical yields of 111In/177Lu-DTPA-CMS were greater than 90% with high radiochemical purities (>98%). Most of the 111In/177Lu-DTPA-CMS were retained in the hepatoma and liver at 1 h after intraarterial (i.a.) administration. Except for liver accumulation, radioactivity in each normal organ was less than 1% of the injected radioactivity (%IA) at 72 h after injection. At 10 days after injection of 177Lu-DTPA-CMS (18.6 ± 1.3 MBq), the size of the hepatoma was significantly reduced by around 81%, while that of the rats in the control group continued to grow. This study demonstrated the effectiveness of 177Lu-DTPA-CMS in the treatment of N1-S1 hepatoma. 111In/177Lu-DTPA-CMS have the potential to be a superior theranostic pair for the treatment of clinical hepatoma.

Metal-organic framework grown in situ on chitosan microspheres as robust host of palladium for heterogeneous catalysis: Suzuki reaction and the p-nitrophenol reduction.

In this study, the metal-organic framework ZIF-8 has been successfully planted on the surface of chitosan microspheres (CS/PDA@ZIF-8) using polydopamine as connecting material for the first time, which avoids the use of expensive, non-renewable, and non-biodegradable polystyrene microspheres commonly used as templates to prepare core-shell structures. Moreover, the metal-organic framework ZIF-8 was prepared specially by three different methods and all characterized by SEM, TEM, and BET, and the ZIF-8 shell prepared at room temperature presents a regular morphology, uniform size, large specific surface area (353.1 m2/g) than the shells prepared by the other methods including. The CS/PDA@ZIF-825@Pd with high catalytic activity and high stability was especially prepared by encapsulating Pd nanoparticles into the pores of CS/PDA@ZIF-825. Notably, the fabricated catalyst performed well in an array of reactions, for example the Kapp value of the p-nitrophenol reduction reaction reached 0.0426 s-1, and the TOF of the Suzuki coupling reaction reached 128 h-1. In addition, the ZIF-67, UiO-66, UiO-66-NH2, HKUST-1, and NH2-MIL-53(Al) were also grown on chitosan microcapsules successively to prepare the core-shell microspheres, which prove the universal applicability of this strategy. And beyond that, the introduction of chitosan microspheres endows the material with biodegradable properties and excellent recycling properties.

Mupirocin-Loaded Chitosan Microspheres Embedded in Piper betle Extract Containing Collagen Scaffold Accelerate Wound Healing Activity.

This study reports the formulation of mupirocin-loaded chitosan microspheres embedded in Piper betle extract containing collagen scaffold as combinational drug delivery for improved wound healing. Selection of chitosan type (molecular weight and degree of deacetylation) was carried out based on their antibacterial efficacy. The low molecular weight chitosan was selected owing to the highest antibacterial action against gram-positive as well as gram-negative bacteria. Low molecular weight chitosan-microspheres showed spherical shape with largely smooth surface morphology, 11.81% of mupirocin loading, and its controlled release profile. The XRD, DSC thermograms, and FT-IR spectral analysis revealed the mupirocin loaded in molecularly dispersed or in amorphous form, and having no chemical interactions with the chitosan matrix, respectively. The in vivo study indicates potential effect of the mupirocin, Piper betle, and chitosan in the collagen scaffold in the wound healing efficiency with approximately 90% wound healing observed at the end of 15 days of study for combinational drug-loaded chitosan microspheres-collagen scaffold-treated group. The histopathology examination further revealed tissue lined by stratified squamous epithelium, collagen deposition, fibroblastic proliferation, and absence of inflammation indicating relatively efficient wound healing once treated with combinational drug-loaded chitosan microspheres containing scaffold.

In vitro evaluation of injectable Tideglusib-loaded hyaluronic acid hydrogels incorporated with Rg1-loaded chitosan microspheres for vital pulp regeneration.

Injectable systems receive attention in endodontics due to the complicated and irregular anatomical structure of root canals. Here, injectable Tideglusib (Td)-loaded hyaluronic acid hydrogels (HAH) incorporated with Rg1-loaded chitosan microspheres (CSM) were developed for vital pulp regeneration, providing release of Td and Rg1 to trigger odontoblastic differentiation of human dental pulp stem cells (DPSC) by Td and vascularization of pulp by Rg1. The optimal concentrations were determined as 90 nM and 50 µg/mL for Td and Rg1, and loaded in HA and CSM in HAH, respectively. Odontogenic (COL1A1, ALP, OCN, Axin-2, DSPP, and DMP1) and angiogenic (VEGFA, VEGFR2, and eNOS) differentiation of DPSC cultured in the presence of hydrogels was shown at gene expression level. Our results suggest that our injectable hydrogel formulation has potential to improve strategies for vital pulp regeneration. In vivo evaluations are needed to test the feasibility and potential of these hydrogels for vital pulp regeneration.