Enhancing antibacterial efficacy and accelerating infectious wound healing in rats using biogenic metal nanoparticles from marine Bacillus subtilis

IntroductionMicroorganisms originating from the marine environment, such as bacteria, fungi, and algae, are deliberately employed in the production of nanoparticles on account of the wide array of bioactive compounds they produce.MethodsCell-free aqueous extracts of marine Bacillus subtilis (CBPPR1) were used to synthesise AuNPs (CBPPR1AuNPs) and AgNPs (CBPPR1AgNPs). Zetasizer Nano ZS (Malvern Instruments) zeta size and zeta potential, field emission and transmission scanning electron microscopy (FE-SEM and HR-TEM), UV-visible (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and EDAX were used to characterize biogenically synthesized nanoparticles (NPs). Their antibacterial activities against Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were investigated. The anticancer efficacy of CBPPR1Au and AgNPs was investigated in human colorectal adenocarcinoma cell lines (HT-29, HT-116). CBPPR1AgNPs formulation was studied in vitro and in-vivo rat models. The assessment focused on its efficacy in wound healing and antibacterial capabilities, comparing them against a commercial product. To determine the effectiveness of CBPPR1AgNPs in wound healing, a cutaneous wound model was employed, which included infection with S. aureus.Results and discusionCBPPR1Au and AgNPs significantly inhibited the growth of S aureus at MIC of 125 µg (CBPPR1AuNPs) and 62.5 µg (CBPPR1AgNPs) respectively. FE-SEM and HR-TEM observations confirmed that NPs caused bacterial cell leakage, damage, and shrinkage. Cancer cell viability was reduced upon treatment with increasing concentrations of CBPPR1Au and AgNPs, and apoptosis was increased in cells treated with CBPPR1Au and AgNPs relative to untreated cells (p < 0.001). CBPPR1Au and AgNPs showed significant cytotoxic activity against HT-29 (15.5 M) and HT-116 (62.5 M) cells. In-vivo experiments on rats showed minimal pus formation in groups CBPPR1AgNPs (62.5 µg/ml) G2, CBPPR1AgNPs (125 µg/ml) G3, and silver sulfadiazine G4, indicating the effective control of infections. CBPPR1AgNPs-treated wounds showed complete closure, whereas untreated G1 wounds remained unhealed. Histopathological analysis showed no adverse effects of CBPPR1AgNPs on kidneys and livers of rats. These findings suggest that CBPPR1AgNPs play a pivotal role in wound healing because of their potent antibacterial properties

When the strategies for cellular selectivity fail. Challenges and surprises in the design and application of fluorescent benzothiadiazole derivatives for mitochondrial staining

This work describes a series of fluorescent 2,1,3-benzothiadiazole derivatives (neutral, singly-charged and doubly-charged) to act as bioprobes for mitochondria. The results showed the flaws in the molecular architecture of this class of fluorophores and our attempts to direct the synthesized derivatives to the organelle. Unexpected results also showed a need for new strategies to predict the cellular selectivity of these derivatives. One of the singly-charged derivatives could stain mitochondria selectively whereas the doubly-charged stained the plasma membrane in an unexpected but highly selective manner. Co-staining experiments confirmed the cellular localization of the new derivatives. EPR experiments demonstrated the fluorescent marker that is selective for mitochondria does not interfere in the ROS production of the cells

A novel dissolution media for testing drug release from a nanostructured polysaccharide-based colon specific drug delivery system: an approach to alternative colon media

Niranjan G Kotla,1,2 Sima Singh,1,3 Balaji Maddiboyina,4 Omprakash Sunnapu,2 Thomas J Webster5,6 1School of Pharmaceutical Sciences, Lovely Professional University, Punjab, India; 2Technologies for the Advancement of Science, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka, India; 3Department of Pharmaceutical Sciences, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India; 4Department of Pharmaceutics, Vishwabharathi College of Pharmaceutical Sciences, Guntur, Andhra Pradesh, India; 5Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 6Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: The aim of this study was to develop a novel microbially triggered and animal-sparing dissolution method for testing of nanorough polysaccharide-based micron granules for colonic drug delivery. In this method, probiotic cultures of bacteria present in the colonic region were prepared and added to the dissolution media and compared with the performance of conventional dissolution methodologies (such as media with rat cecal and human fecal media). In this study, the predominant species (such as Bacteroides, Bifidobacterium, Lactobacillus species, Eubacterium and Streptococcus) were cultured in 12% w/v skimmed milk powder and 5% w/v grade “A” honey. Approximately 1010–1011 colony forming units m/L of probiotic culture was added to the dissolution media to test the drug release of polysaccharide-based formulations. A USP dissolution apparatus I/II using a gradient pH dissolution method was used to evaluate drug release from formulations meant for colonic drug delivery. Drug release of guar gum/Eudragit FS30D coated 5-fluorouracil granules was assessed under gastric and small intestine conditions within a simulated colonic environment involving fermentation testing with the probiotic culture. The results with the probiotic system were comparable to those obtained from the rat cecal and human fecal-based fermentation model, thereby suggesting that a probiotic dissolution method can be successfully applied for drug release testing of any polysaccharide-based oral formulation meant for colonic delivery. As such, this study significantly adds to the nanostructured biomaterials’ community by elucidating an easier assay for colonic drug delivery. Keywords: probiotic media, colon specific drug delivery, dissolution methodologies, simulated colonic media, microbially triggered drug deliver

A nanomedicine-promising approach to provide an appropriate colon-targeted drug delivery system for 5-fluorouracil

Sima Singh,1,* Niranjan G Kotla,2,* Sonia Tomar,3 Balaji Maddiboyina,4 Thomas J Webster,5,6 Dinesh Sharma,7 Omprakash Sunnapu2 1Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 2Technologies for the Advancement of Science, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka, 3Department of Pharmaceutics, Ram Gopal College of Pharmacy, Rohtak, Haryana, 4Department of Pharmaceutics, Maharishi Markandeshwar University, Mullana, Ambala, Haryana, India; 5Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 6Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia; 7Ranbaxy Laboratory Ltd, Gurgaon, Haryana, India *These authors contributed equally to this work Abstract: Targeted drug delivery plays a significant role in disease treatment associated with the colon, affording therapeutic responses for a prolonged period of time with low side effects. Colorectal cancer is the third most common cancer in both men and women with an estimated 102,480 cases of colon cancer and 40,340 cases of rectal cancer in 2013 as reported by the American Cancer Society. In the present investigation, we developed an improved oral delivery system for existing anticancer drugs meant for colon cancer via prebiotic and probiotic approaches. The system comprises three components, namely, nanoparticles of drug coated with natural materials such as guar gum, xanthan gum (that serve as prebiotics), and probiotics. The natural gums play a dual role of protecting the drug in the gastric as well as intestinal conditions to allow its release only in the colon. In vitro results obtained from these experiments indicated the successful targeted delivery of 5-fluorouracil to the colon. Electron microscopy results demonstrated that the prepared nanoparticles were spherical in shape and 200 nm in size. The in vitro release data indicated that the maximum release occurs at pH 7.2 and 7.4 with 93% of the drug released in the presence of 4% (w/v) of rat cecal content. In vivo results conclude a practical mechanism to maintain the integrity and intactness of the intestinal/colonic microflora, in the face of a “chemical attack” by oral colon-targeted drug delivery for colon cancer treatment. Keywords: colon-specific drug delivery system, polymeric nanoparticles, probiotics, 5-fluorouraci