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The use of novel antimicrobial molecules in bone cement can improve efficiency of recuperation after arthroplasty or joint replacement surgeries, avoiding the risks associated with antibiotic resistant antimicrobial agents. Nanomaterials particularly dendrimers are particularly useful for making broad spectrum killing agents owing to their large surface areas and functionalities. Therefore, we have synthesized generation 1 quaternary ammonium dendrimer of tripropylene glycol diacrylate (TPGDA) using octyl iodide (OI) [TPGDA G1.0 (=) quaternary octyl iodide (QOI)] and capitalized on their capabilities of contact killing based mechanism. We formulated different TPGDA G1.0 (=) QOI antimicrobial agent loaded liquid component composed of methyl methacrylate monomer and N,N-dimethyl-p-toluidine coinitiator. Different polymethyl methacrylate (PMMA) based experimental bone cement formulations were made and dendrimer concentration was optimized. Mechanical strength and compressive modulus of modified bone cement decreased on increasing concentrations and 10% was optimized for further analysis. The mechanical strength of bone cement yield the similar trend in wet conditions bone cement immersed in artificially created stimulated body fluids. Ten percent TPGDA G1.0 (=) QOI in bone cement was sufficient to kill gram positive and negative bacteria and its property is retained even after a period of 30 days. Thus novel dendritic structures show promise for clinical antimicrobial activity while retaining mechanical properties of bone cements. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 521-530, 2017.

Bioconjugation of quantum dots has resulted in a significant increase in resolution of biological fluorescent labeling. This intrinsic property of quantum dots can be utilized for sensitive detection of target analytes with high sensitivity; including pathogenic bacteria and cancer monitoring. The quantum dots and quantum dot doped silica nanoparticles exhibit prominent emission peaks when excited at 400 nm but on conjugation to model rabbit antigoat antibodies exhibit diminished intensity of emission peak at 600 nm. It shows that photoluminescence intensity of conjugated quantum dots and quantum dot doped silica nanoparticles could permit the detection of bioconjugation. Samples of conjugated and unconjugated quantum dots and quantum dot doped silica nanoparticles were subjected to enzyme linked immunosorbent assay for further confirmation of bioconjugation. In the present study ligand exchange, bioconjugation, fluorescence detection of bioconjugated quantum dots and quantum dot doped silica nanoparticles and further confirmation of bioconjugation by enzyme linked immunosorbent assay has been described.

Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable, monodisperse, spherical nano sized particles exhibiting high luminescence properties. Particles with 1% SLS (S1) showed good dispersion stability and fluorescence intensity and were chosen as ideal candidates for further immobilization studies. Steady state fluorescence studies showed 10 times higher fluorescence intensity of S1 nanoparticles than that of pyrene solution in solvent-toluene at the same concentration. Environmental factors such as pH, ionic strength and time were found to have no effect on fluorescence intensity of FPNPs. Surface β-di-ketone groups were utilized for the covalent immobilization of enzyme conjugated antibodies without any activation or pre-treatment of nanoparticles.