Publications

Bone regeneration using inorganic nanoparticles is a robust and safe approach. In this paper, copper nanoparticles (Cu NPs) loaded with calcium phosphate scaffolds were studied for their bone regeneration potential in vitro. The pneumatic extrusion method of 3D printing was employed to prepare calcium phosphate cement (CPC) and copper loaded CPC scaffolds with varying wt% of copper nanoparticles. A new aliphatic compound Kollisolv MCT 70 was used to ensure the uniform mixing of copper nanoparticles with CPC matrix. The printed scaffolds were studied for physico-chemical characterization for surface morphology, pore size, wettability, XRD, and FTIR. The copper ion release was studied in phosphate buffer saline at pH 7.4. The in vitro cell culture studies for the scaffolds were performed using human mesenchymal stem cells (hMSCs). The cell proliferation study in CPC-Cu scaffolds showed significant cell growth compared to CPC. The CPC-Cu scaffolds showed improved alkaline phosphatase activity and angiogenic potential compared to CPC. The CPC-Cu scaffolds showed significant concentration dependent antibacterial activity in Staphylococcus aureus. Overall, the CPC scaffolds loaded with 1 wt% Cu NPs showed improved activity compared to other CPC-Cu and CPC scaffolds. The results showed that copper has improved the osteogenic, angiogenic and antibacterial properties of CPC scaffolds, facilitating better bone regeneration in vitro.

Selective laser sintering (SLS) is a single-step, three-dimensional printing (3DP) process that is gaining momentum in the manufacturing of pharmaceutical dosage forms. It also offers opportunities for manufacturing various pharmaceutical dosage forms with a wide array of drug delivery systems. This research aimed to introduce carbonyl iron as a multifunctional magnetic and heat conductive ingredient for the fabrication of oral tablets containing isoniazid, a model antitubercular drug, via SLS 3DP process. Furthermore, the effects of magnetic iron particles on the drug release from the SLS printed tablets under a specially designed magnetic field was studied. Optimization of tablet quality was performed by adjusting SLS printing parameters. The independent factors studied were laser scanning speed, hatching space, and surface/chamber temperature. The responses measured were printed tablets' weight, hardness, disintegration time, and dissolution performance. It has been observed that, for the drug formulation with carbonyl iron, due to its inherent thermal conductivity, sintering tablets required relatively lower laser energy input to form the tablets of the same quality attributes as the other batches that contained no magnetic particles. Also, printed tablets with carbonyl iron released 25% more drugs under a magnetic field than those without it. It can be claimed that magnetic nanoparticles appear as an alternative conductive material to facilitate the sintering process during SLS 3DP of dosage forms.

Three-dimensional (3D) bioprinting is an emerging biofabrication technique that shows great potential in the field of tissue engineering, regenerative medicine and advanced drug delivery. Despite the current advancement of bioprinting technology, it faces several obstacles such as the challenge of optimizing the printing resolution of 3D constructs while retaining cell viability before, during, and after bioprinting. Therefore, it is of great significance to fully understand factors that influence the shape fidelity of printed structures and the performance of cells encapsulated in bioinks. This review presents a comprehensive analysis of bioprinting process parameters that influence bioink printability and cell performance, including bioink properties (composition, concentration, and component ratio), printing speed and pressure, nozzle characteristics (size, length, and geometry), and crosslinking parameters (crosslinker types, concentration, and crosslinking time). Key examples are provided to analyze how these parameters could be tailored to achieve the optimal printing resolution as well as cell performance. Finally, future prospects of bioprinting technology, including correlation between process parameters and particular cell types with predefined applications, applying statistical analysis and artificial intelligence (AI)/machine learning (ML) technique in parameter screening, and optimizing four-dimensional (4D) bioprinting process parameters, are highlighted.

Gene therapy is a promising approach with delivery of mRNA, small interference RNA, and plasmid DNA to elicit a therapeutic action in vitro using cationic or ionizable lipid nanoparticles. In the present study, a novel extrusion-based Sprayed Multi Adsorbed-droplet Reposing Technology (SMART) developed in-house was employed for the preparation, characterization, and transfection abilities of the green fluorescence protein (GFP) plasmid DNA in cancer cells in vitro. The results showed 100% encapsulation of pDNA (GFP) in LNPs of around 150 nm (N/P 5) indicating that the processes developed using SMART technology are consistent and can be utilized for commercial applications.

The in situ injectable hydrogel system offers a widespread range of biomedical applications in prompt chronic wound treatment and management, as it provides self-healing, maintains a moist wound microenvironment, and offers good antibacterial properties. This study aimed to develop and evaluate biopolymer-based thermoreversible injectable hydrogels for effective wound-healing applications and the controlled drug delivery of meropenem. The injectable hydrogel was developed using the solvent casting method and evaluated for structural changes using proton nuclear magnetic resonance, Fourier transforms infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The results indicated the self-assembly of hyaluronic acid and kappa-carrageenan and the thermal stability of the fabricated injectable hydrogel with tunable gelation properties. The viscosity assessment indicated the in-situ gelling ability and injectability of the hydrogels at various temperatures. The fabricated hydrogel was loaded with meropenem, and the drug release from the hydrogel in phosphate buffer saline (PBS) with a pH of 7.4 was 96.12%, and the simulated wound fluid with a pH of 6.8 was observed to be at 94.73% at 24 h, which corresponds to the sustained delivery of meropenem. Antibacterial studies on P. aeruginosa, S. aureus, and E. coli with meropenem-laden hydrogel showed higher zones of inhibition. The in vivo studies in Sprague Dawley (SD) rats presented accelerated healing with the drug-loaded injectable hydrogel, while 90% wound closure with the unloaded injectable hydrogel, 70% in the positive control group (SC drug), and 60% in the negative control group was observed (normal saline) after fourteen days. In vivo wound closure analysis confirmed that the developed polymeric hydrogel has synergistic wound-healing potential.

Despite the fact that capsules play an important role in many dry powder inhalation (DPI) systems, few studies have been conducted to investigate the capsules' interactions with respirable powders. The effect of four commercially available hydroxypropyl methylcellulose (HPMC)inhalation-grade capsule types on the aerosol performance of two model DPI formulations (lactose carrier and a carrier-free formulation) at two different pressure drops was investigated in this study. There were no statistically significant differences in performance between capsules by using the carrier-based formulation. However, there were some differences between the capsules used for the carrier-free rifampicin formulation. At 2-kPa pressure drop conditions, Embocaps® VG capsules had a higher mean emitted fraction (EF) (89.86%) and a lower mean mass median aerodynamic diameter (MMAD) (4.19 µm) than Vcaps® (Capsugel) (85.54%, 5.10 µm) and Quali-V® I (Qualicaps) (85.01%, 5.09 µm), but no significant performance differences between Embocaps® and ACGcaps™ HI. Moreover, Embocaps® VG capsules exhibited a higher mean respirable fraction (RF)/fine particle fraction (FPF) with a 3-µm-sized cutoff (RF/FPF< 3 µm) (33.05%/35.36%) against Quali-V® I (28.16%/31.75%) (P < 0.05), and a higher RF/FPF with a 5-µm-sized cutoff (RF/FPF< 5 µm) (49.15%/52.57%) versus ACGcaps™ HI (38.88%/41.99%) (P < 0.01) at 4-kPa pressure drop condition. Aerosol performance variability, pierced-flap detachment, as well as capsule hardness and stiffness, may all influence capsule type selection in a carrier-based formulation. The capsule type influenced EF, RF, FPF, and MMAD in the carrier-free formulation.

Bacteriotherapy has proved to be a powerful tool to fight against cancer. Herein, we used VOSviewer, CiteSpace, and Python to perform the first global bibliometric analysis of the literature from 2012 to 2021 on bacteria-mediated cancer therapy. Based on the results, East Asia and North America contributed the most publications to this research area. Additionally, the keyword analysis indicated that immunotherapy and nanoparticle (NP)-based drug delivery systems have long been popular topics in cancer bacteriotherapy, whereas the gut microbiota and probiotics are emerging research hotspots. This study provides crucial insights into the historical development of bacteria-mediated cancer therapy from 2012 to 2021, which will be helpful for scientists to conduct further investigation into this promising field.

Recently, various innovative technologies have been developed for the enhanced delivery of biologics as attractive formulation targets including polymeric micro and nanoparticles. Combined with personalized medicine, this area can offer a great opportunity for the improvement of therapeutics efficiency and the treatment outcome. Herein, a novel manufacturing method has been introduced to produce protein-loaded chitosan particles with controlled size. This method is based on an additive manufacturing technology that allows for the designing and production of personalized particulate based therapeutic formulations with a precise control over the shape, size, and potentially the geometry. Sprayed multi adsorbed-droplet reposing technology (SMART) consists of the high-pressure extrusion of an ink with a well determined composition using a pneumatic 3D bioprinting approach and flash freezing the extrudate at the printing bed, optionally followed by freeze drying. In the present study, we attempted to manufacture trypsin-loaded chitosan particles using SMART. The ink and products were thoroughly characterized by dynamic light scattering, rheometer, Scanning Electron Microscopy (SEM), and Fourier Transform Infra-Red (FTIR) and Circular Dichroism (CD) spectroscopy. These characterizations confirmed the shape morphology as well as the protein integrity over the process. Further, the effect of various factors on the production were investigated. Our results showed that the concentration of the carrier, chitosan, and the lyoprotectant concentration as well as the extrusion pressure have a significant effect on the particle size. According to CD spectra, SMART ensured Trypsin's secondary structure remained intact regardless of the ink composition and pressure. However, our study revealed that the presence of 5% (w/v) lyoprotectant is essential to maintain the trypsin's proteolytic activity. This study demonstrates, for the first time, the viability of SMART as a single-step efficient process to produce biologics-based stable formulations with a precise control over the particulate morphology which can further be expanded across numerous therapeutic modalities including vaccines and cell/gene therapies.

Current microparticle (MP) development still strongly relies on the laborious trial-and-error approach. Herein, we developed a systemic method to evaluate the significance of MP formulation factors and predict drug loading efficiency (DLE) using design of experiment (DoE) and machine learning modeling. A first-in-class 3D printing concept was initially employed to fabricate polymeric MPs by a 3D printer. Sprayed Multi Adsorbed-droplet Reposing Technology (SMART) was developed to combine extrusion-based printing with emulsion evaporation technique to fabricate a small molecule drug i.e., 6-thioguanine (6-TG) loaded poly (lactide-co-glycolide) (PLGA) MPs. Compared to conventional emulsion evaporation method, SMART employs the shear force exerted by the printing nozzle rather than the sonication energy to generate smaller emulsion droplets in a single step. Furthermore, the applied shear force in the 3D printing process reported herein is controllable since the emulsion is extruded through the nozzle under preset printing conditions. The formulated MPs exhibited spherical structure with size distribution ∼ 1-3μ m in diameter and reached ∼ 100 % drug release at 10 h. Also, the papain-like protease (PLpro) inhibition efficacy of 6-TG in formulated MPs was maintained even after the printing process under different printing conditions. Furthermore, the formulation factor importance was assessed by DoE statistical analysis and further validated by machine learning modeling. Among the four process parameters (drug amount, printing speed, printing pressure, and nozzle size), drug amount was the most influential formulation factor. Moreover, it is interesting that nearly all the machine learning models, especially decision tree (DT), demonstrated superior performance in predicting DLE compared to DoE regression models. Overall, incorporating DoE and machine learning modeling shows great promises in the prediction and optimization of MP formulations factors by means of a novel SMART technology. Moreover, this systemic approach helps streamline the development of MP with programmable pharmaceutical attributes, representing a new paradigm for digital pharmaceutical science.

This study demonstrates the applicability of terahertz time-domain spectroscopy (THz-TDS) in evaluating the solid-state of the drug in selective laser sintering-based 3D printed dosage forms. Selective laser sintering is a powder bed-based 3D printing platform, which has recently demonstrated applicability in manufacturing amorphous solid dispersions (ASDs) through a layer-by-layer fusion process. When formulating ASDs, it is critical to confirm the final solid state of the drug as residual crystallinity can alter the performance of the formulation. Moreover, SLS 3D printing does not involve the mixing of the components during the process, which can lead to partially amorphous systems causing reproducibility and storage stability problems along with possibilities of unwanted polymorphism. In this study, a previously investigated SLS 3D printed ASD was characterized using THz-TDS and compared with traditionally used solid-state characterization techniques, including differential scanning calorimetry (DSC) and powder X-ray diffractometry (pXRD). THz-TDS provided deeper insights into the solid state of the dosage forms and their properties. Moreover, THz-TDS was able to detect residual crystallinity in granules prepared using twin-screw granulation for the 3D printing process, which was undetectable by the DSC and XRD. THz-TDS can prove to be a useful tool in gaining deeper insights into the solid-state properties and further aid in predicting the stability of amorphous solid dispersions.