Ranjith Kumar Kankala

Investigation of silk fibroin nanoparticle-decorated poly(L-lactic acid) composite scaffolds for osteoblast growth and differentiation

Attempts to reflect the physiology of organs is quite an intricacy during the tissue engineering process. An ideal scaffold and its surface topography can address and manipulate the cell behavior during the regeneration of targeted tissue, affecting the cell growth and differentiation significantly. Herein, silk fibroin (SF) nanoparticles were incorporated into poly(l-lactic acid) (PLLA) to prepare composite scaffolds via phase-inversion technique using supercritical carbon dioxide (SC-CO2). The SF nanoparticle core increased the surface roughness and hydrophilicity of the PLLA scaffolds, leading to a high affinity for albumin attachment. The in vitro cytotoxicity test of SF/PLLA scaffolds in L929 mouse fibroblast cells indicated good biocompatibility. Then, the in vitro interplay between mouse preosteoblast cell (MC3T3-E1) and various topological structures and biochemical cues were evaluated. The cell adhesion, proliferation, osteogenic differentiation and their relationship with the structures as well as SF content were explored. The SF/PLLA weight ratio (2:8) significantly affected the MC3T3-E1 cells by improving the expression of key players in the regulation of bone formation, ie, alkaline phosphatase (ALP), osteocalcin (OC) and collagen 1 (COL-1). These results suggest not only the importance of surface topography and biochemical cues but also the potential of applying SF/PLLA composite scaffolds as biomaterials in bone tissue engineering.

Supercritical Fluid Technology: An Emphasis on Drug Delivery and Related Biomedical Applications

During the past few decades, supercritical fluid (SCF) has emerged as an effective alternative for many traditional pharmaceutical manufacturing processes. Operating active pharmaceutical ingredients (APIs) alone or in combination with various biodegradable polymeric carriers in high-pressure conditions provides enhanced features with respect to their physical properties such as bioavailability enhancement, is of relevance to the application of SCF in the pharmaceutical industry. Herein, recent advances in drug delivery systems manufactured using the SCF technology are reviewed. We provide a brief description of the history, principle, and various preparation methods involved in the SCF technology. Next, we aim to give a brief overview, which provides an emphasis and discussion of recent reports using supercritical carbon dioxide (SC-CO2) for fabrication of polymeric carriers, for applications in areas related to drug delivery, tissue engineering, bio-imaging, and other biomedical applications. We finally summarize with perspectives.

Overcoming multidrug resistance through co-delivery of ROS-generating nano-machinery in cancer therapeutics

The use of nanotechnology to overcome multidrug resistance (MDR) in cancer cells has been predominant. Herein, we report the conjugation of copper(ii)-doxorubicin complexes on the surfaces of layered double hydroxide nanoparticles (LDHs) along with ascorbic acid intercalation in the gallery space to demonstrate synergistic effects to conquer MDR. The pH-sensitive release of doxorubicin (Dox) and the sustained release of ascorbic acid (AA) generate high amounts of hydrogen peroxide intracellularly that concomitantly results in conversion to cytotoxic free radicals through a copper(ii)-catalyzed Fenton-like reaction. Therefore, the combination of the chemotherapeutic agent (Dox) and free radical attack can devastate the MDR for effective cancer treatment through the co-delivery system.

Fabrication of arbitrary 3D components in cardiac surgery: from macro-, micro- to nanoscale

Fabrication of tissue-/organ-like structures at arbitrary geometries by mimicking the properties of the complex material offers enormous interest to the research and clinical applicability in cardiovascular diseases. Patient-specific, durable, and realistic three-dimensional (3D) cardiac models for anatomic consideration have been developed for education, pro-surgery planning, and intra-surgery guidance. In cardiac tissue engineering (TE), 3D printing technology is the most convenient and efficient microfabrication method to create biomimetic cardiovascular tissue for the potential in vivo implantation. Although booming rapidly, this technology is still in its infancy. Herein, we provide an emphasis on the application of this technology in clinical practices, micro- and nanoscale fabrications by cardiac TE. Initially, we will give an overview on the fabrication methods that can be used to synthesize the arbitrary 3D components with controlled features and will subsequently highlight the current limitations and future perspective of 3D printing used for cardiovascular diseases.

Phototherapeutic spectrum expansion through synergistic effect of mesoporous silica trio-nanohybrids against antibiotic-resistant gram-negative bacterium

The extensive impact of antibiotic resistance has led to the exploration of new anti-bacterial modalities. We designed copper impregnated mesoporous silica nanoparticles (Cu-MSN) with immobilizing silver nanoparticles (SNPs) to apply photodynamic inactivation (PDI) of antibiotic-resistant E. coli. SNPs were decorated over the Cu-MSN surfaces by coordination of silver ions on diamine-functionalized Cu-MSN and further reduced to silver nanoparticles with formalin. We demonstrate that silver is capable of sensitizing the gram-negative bacteria E. coli to a gram-positive specific phototherapeutic agent in vitro; thereby expanding curcumins phototherapeutic spectrum. The mesoporous structure of Cu-MSN remains intact after the exterior decoration with silver nanoparticles and subsequent curcumin loading through an enhanced effect from copper metal-curcumin affinity interaction. The synthesis, as well as successful assembly of the functional nanomaterials, was confirmed by various physical characterization techniques. Curcumin is capable of producing high amounts of reactive oxygen species (ROS) under light irradiation, which can further improve the silver ion release kinetics for antibacterial activity. In addition, the positive charged modified surfaces of Cu-MSN facilitate antimicrobial response through electrostatic attractions towards negatively charged bacterial cell membranes. The antibacterial action of the synthesized nanocomposites can be activated through a synergistic mechanism of energy transfer of the absorbed light from SNP to curcumin.

3D-Printing of Microfibrous Porous Scaffolds Based on Hybrid Approaches for Bone Tissue Engineering

In recent times, tremendous progress has been evidenced by the advancements in various methods of generating three-dimensional (3D) porous scaffolds. However, the applicability of most of the traditional approaches intended for generating these biomimetic scaffolds is limited due to poor resolution and strict requirements in choosing materials. In this work, we fabricated 3D porous scaffolds based on the composite inks of gelatin (Gel), nano-hydroxyapatite (n-HA), and poly(lactide-co-glycolide) (PLGA) using an innovative hybrid strategy based on 3D printing and freeze-drying technologies for bone tissue engineering. Initially, the PLGA scaffolds were printed using the 3D printing method, and they were then coated with the Gel/n-HA complex, yielding the Gel/n-HA/PLGA scaffolds. These Gel/n-HA/PLGA scaffolds with exceptional biodegradation, mechanical properties, and biocompatibility have enabled osteoblasts (MC3T3-E1) for their convenient adhesion as a layer and have efficiently promoted their growth, as well as differentiation. We further demonstrated the bone growth by measuring the particular biomarkers that act as key players in the ossification process (i.e., alkaline phosphatase (ALP), osteocalcin (OC), and collagen type-I (COL-I)) and the total proteins of the MC3T3-E1 cells. We anticipate that the convenient generation of highly porous 3D scaffolds based on Gel/n-HA/PLGA fabricated through an innovative combinatorial approach of 3D printing technology and freeze-drying methods may undoubtedly find widespread applications in regenerative medicine.

Synthesis and characterization of innovative poly(lactide-co-glycolide)-(poly-L-ornithine/fucoidan) core–shell nanocarriers by layer-by-layer self-assembly

Layer-by-Layer (LbL) self-assembly of nanocarriers has garnered the interest of researchers for a wide variety of biomedical applications. In this study, we demonstrated the preparation of poly(lactide-co-glycolide) (PLGA)-(poly-L-ornithine (PLO)/fucoidan)4 core–shell nanoparticles (LbL NPs) by a LbL-based self-assembly process, which possessed a mean size of 170 nm. In LbL NPs, a drug carrying PLGA nano-core is coated with alternating PLO and sulfated polysaccharide fucoidan composite films as a shell on the surface. The anti-tumor drug doxorubicin (DOX) loaded into the PLGA core, resulted in better encapsulation efficiency and its in vitro release from LbL NPs demonstrates that this core–shell strategy takes an advantage of its ability to hold the drug cargo and exhibit controlled release. Further, in vitro cell uptake studies by confocal laser scanning microscopy (CLSM) examination in breast tumor cells (MCF-7 cell line) have confirmed that the nanocarriers are successfully internalized and outlined their presence in the cytoplasm after 4 h of incubation. These intracellularly delivered DOX-loaded LbL NPs exhibited significant anti-tumor activity against breast tumor cells. This innovative chemotherapeutic design taking above advantages of successful internalization along with controlled release property signifies as a promising interventional therapeutic delivery system.

Solution-enhanced dispersion by supercritical fluids: an ecofriendly nanonization approach for processing biomaterials and pharmaceutical compounds

In recent years, the supercritical fluid (SCF) technology has attracted enormous interest from researchers over the traditional pharmaceutical manufacturing strategies due to the environmentally benign nature and economically promising character of SCFs. Among all the SCF-assisted processes for particle formation, the solution-enhanced dispersion by supercritical fluids (SEDS) process is perhaps one of the most efficient methods to fabricate the biomaterials and pharmaceutical compounds at an arbitrary gauge, ranging from micro- to nanoscale. The resultant miniature-sized particles from the SEDS process offer enhanced features concerning their physical attributes such as bioavailability enhancement due to their high surface area. First, we provide a brief description of SCFs and their behavior as an anti-solvent in SCF-assisted processing. Then, we aim to give a brief overview of the SEDS process as well as its modified prototypes, highlighting the pros and cons of the particular modification. We then emphasize the effects of various processing constraints such as temperature, pressure, SCF as well as organic solvents (if used) and their flow rates, and the concentration of drug/polymer, among others, on particle formation with respect to the particle size distribution, precipitation yield, and morphologic attributes. Next, we aim to systematically discuss the application of the SEDS technique in producing therapeutic nano-sized formulations by operating the drugs alone or in combination with the biodegradable polymers for the application focusing oral, pulmonary, and transdermal as well as implantable delivery with a set of examples. We finally summarize with perspectives.

Effect of Icariin on Engineered 3D-Printed Porous Scaffolds for Cartilage Repair

In recent times, cartilage defects have been the most common athletic injuries, often leading to dreadful consequences such as osteoarthritis, pain, joint deformities, and other symptoms. It is also evident that damage to articular cartilage is often difficult to recover or self-heal because of poor vascular, nervous, and lymphatic supplies. Moreover, cartilage cells have poor regeneration ability and high maturity. Inspired by these facts and the rapid advances in the field of tissue engineering (TE), we fabricated highly porous three-dimensional (3D) scaffold architectures based on cell-responsive polymeric inks, i.e., sodium alginate and gelatin (SA-Gel, 1:3 ratio), by a novel 3D printing method. Moreover, the effect of various processing parameters was systematically investigated. The printed scaffolds of polymer composites gels with excellent transparency, moderate viscosity, and excellent fluid properties showed good surface morphology, better thermal stability and swelling effect, and unique interconnected porous architectures at the optimized operating parameters. In vitro cell proliferation experiments of these cytocompatible scaffolds showed the excellent adhesion rate and growth behavior of chondrocytes. In addition, the porous architectures facilitated the efficient distribution of cells with only a few remaining on the surface, which was confirmed by confocal laser scanning microscopic (CLSM) observations. Icariin (ICA) addition at a concentration of 10 μg/mL further significantly enhanced the proliferation of chondrocytes. We envision that these cell-responsive polymeric inks in the presence of growth regulators like ICA may have potential in engineering complex tissue constructs toward diverse applications in TE.

Preparation of a MVL-Ca-Alg/CS MEMs system with add-on effect for type 2 diabetes treatment

ABSTRACT Add-on drugs, often called as synergistic therapy, for diabetes have been comparatively more promising as they can reduce the systemic adverse effects resulted during respective monotherapy [metformin (MET)/insulin (INS)]. Herewith, we formulated a multivesicular liposome microparticles-embedded Ca-Alg/chitosan microcapsules (MVL-Ca-Alg/CS MEMs) system by a double-emulsion method using a high voltage electrostatic droplet generator. Physical characterization of the designed formulation was elucidated based on particle size and distribution, drug loading and encapsulation efficiency, drug delivery properties, and pharmacodynamic evaluation. The multivesicular liposomes microparticles (MVLs MPs) and MVL-Ca-Alg/CS MEMs have shown good sphericity and dispersion, and the average diameters were 37 and 491 µm, respectively. The confocal laser scanning microscopic observations demonstrated that fluorescein isothiocyanate-conjugated INS is uniformly dispersed in MVLs MPs, predominantly within the lumen of the polycystic liposome. This multicomponent system possessing INS in the inner space and MET at the outer space resulted in orderly and sustained drug release patterns. Furthermore, the obtained in vivo experimental data have shown that the designed MEMs system resulted in significantly higher hypoglycemic effect compared to pure INS, demonstrating that our multicomponent design has an enormous potential for treating diabetes. GRAPHICAL ABSTRACT