Recent advances of biosensors in biomedical sciences

This review discusses recent advances in biosensor technology which draw on the disciplines of physics, chemistry, biochemistry and electronics. We first show that a biosensor consists of three components, a biological detection system, a transducer and an output system. Biological receptors are reviewed, followed by a detailed discussion of transducers, optical, electrochemical, piezoelectric, and others which involve interesting physics and show particular promise for commercial biosensors, are discussed thoroughly. New developments in biosensor design are appearing at a high rate as these devices play increasingly important roles in daily life. We describe a new technology, the Ibis T5000, for the identification of pathogens in clinical and environmental samples; a novel ion channel switch biosensor (ICSB), offers a rapid and sensitive immunodiagnostic for viral detection at point-of care; Chip-NMR, new diagnostic platforms have been developed to measure biomolecule abundance with high sensitivity; Graphene has attracted strong scientific and technological interest in recent years. Finally, future trends in biosensor development are discussed. In this context, bioelectronics, miniaturization, and especially biotechnology seem to be growing areas that will have a marked influence on the development of new biosensing strategies in the next future

Antibacterial activity of actinomycetes isolated from different soil samples of Sheopur (A city of central India)

The main objective of the present study was isolation, purification, and characterization of actinomycetes from soil samples, having antimicrobial activity against 12 selected pathogenic strains. Soils samples were taken from different niche habitats of Sheopur district, Madhya Pradesh, India. These samples were serially diluted and plated on actinomycete isolation agar media. Potential colonies were screened, purified, and stored in glycerol stock. Isolates were morphologically and biochemically characterized. These isolates were subjected to extraction for production of the antibacterial compound. Antibacterial activity and Minimum Inhibitory Concentration (MIC) of the purified extract of isolates were evaluated. Totally 31 actinomycete isolates were tested for antagonistic activity against 12 pathogenic microorganisms. Isolates AS14, AS27, and AS28 were highly active, while AS1 showed less activity against the pathogenic microorganisms. Isolate AS7 exhibited the highest antagonistic activity against Bacillus cereus (24 mm) and AS16 showed the highest activity against Enterococcus faecalis (21 mm). MIC was also determined for actinomycete isolates against all the tested microorganisms. MIC of actinomycete isolates was found to be 2.5 mg/ml against Shigella dysenteriae, Vancomycin-resistant enterococci, and Klebsiella pneumoniae, and was 1.25 mg/ml for Staphylococcus saprophyticus, Streptococcus pyogenes, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus, Bacillus cereus, Staphylococcus xylosus, Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, and Staphylococcus aureus. All actinomycetes isolates showed antibacterial activity against S. aureus, while they showed less activity against S. dysenteriae. These isolates had antibacterial activity and could be used in the development of new antibiotics for pharmaceutical or agricultural purposes

Effect Of Withania somnifera Leaf Extracts As Antibacterial Agent Against Multidrug Resistant Bacteria

This study was designed to examine the phytochemical composition and to evaluate antibacterial potential of Withania Somnifera leaf against multidrug resistant bacteria & FT-IR Spectra of different bioactive compounds. Toluene, ethanol, and aqueous extracts of W. Somnifera (leaves) were subjected for in vitro antibacterial activity using agar well diffusion against different bacteria of clinical relevance including multi-drug resistant methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus (VRE) sps.The toluene extract resulted maximal active as antibacterial agent and found significantly higher active than aqueous extract (P<0.05). The difference between antibacterial activities of toluene and ethanol or ethanol and aqueous extract was statistically non significant (P>0.05). The maximum activity was observed against Staphylococcus aureus. The extracts (at least one) also showed antibacterial activity against Bacillus cereus, coagulase negative staphylococcus, Streptococcus pneumoinae, Shigella dysenteriae, Methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus (VRE) sps. Minimum inhibitory concentrations of plant extract were found in the ranges of 0.156mg/ml to 0.625mg/ml for test strains. Phytochemical analyses revealed the presence of various metabolites like phlobtannins, tannins, steroids and alkaloids which may contribute for the antimicrobial action of leaves extract of W. Somnifera. The partial characterization of the crude extracts by IR spectral analysis revealed the possible presence of different bioactive compounds in the extracts. The leaves of W. Somnifera showed promising antibacterial activity against various clinically important bacteria and multidrug resistant MRSA and VRE.

Distribution of airborne microbes and antibiotic susceptibility pattern of bacteria during Gwalior trade fair, Central India

Research into the distribution of bioaerosols during events associated with huge groups of people is lacking, especially in developing countries. The purpose of this study was to understand the distribution pattern of bioaerosols during an annual trade fair in the historical city of Gwalior, central India, a very important historical fair that was started by the King of Gwalior Maharaja Madho Rao in 1905. Methods: Air samples were collected from six different sites at the fair ground and three different sites in a residential area before/during/after the fair using an impactor sampler on microbial content test agar and rose bengal agar for total bacteria and fungi, respectively. The representative strains of bacteria and fungi were further identified and selected bacterial strains were subjected to antibiotic susceptibility testing according to US Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: The bacterial bioaerosol count [colony-forming units (CFU)/m3] at fair sites was found to be 9.0 × 103, 4.0 × 104, and 1.0 × 104 before the start of the fair, during the fair, and after the fair, respectively. The fungal bioaerosol count at fair sites was 2.6 × 103 CFU/m3, 6.3 × 103 CFU/m3, and 1.7 × 103 CFU/m3 before the fair, during the fair, and after the fair, respectively. Bacterial/fungal bioaerosols during-fair were increased significantly from the bacterial/fungal bioaerosols of the before-fair period (p < 0.05); they were also significantly higher than the bacterial/fungal bioaerosols at non-fair sites during the event (p < 0.0001). The proportion of antibiotic-resistant bacteria over the fair ground was significantly increased during-fair and was still higher in the after-fair period. Methicillin-resistant staphylococci (MRS) were also reported at the fair ground. Conclusion: The study indicates significantly higher bacterial and fungal bioaerosols during the fair event. Therefore, further research is needed to explore the health aspects and guidelines to control microbial load during such types of events