The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future.

Porphyrins have been used for photodynamic therapy (PDT) against a wide range of targets like bacteria, viruses and tumor cells. In this work, we report porphyrin-conjugated multi-walled carbon nanotubes (NT-P) as potent antiviral agents. Specifically, we used Protoporphyrin IX (PPIX), which we attached to acid-functionalized multi-walled carbon nanotubes (MWNTs). We decided to use carbon nanotubes as scaffolds because of their ease of recovery from a solution through filtration. In the presence of visible light, NT-P was found to significantly reduce the ability of Influenza A virus to infect mammalian cells. NT-P may be used effectively against influenza viruses with little or no chance of them developing resistance to the treatment. Furthermore, NT-P can be easily recovered through filtration which offers a facile strategy to reuse the active porphyrin moiety to its fullest extent. Thus NT-P conjugates represent a new approach for preparing ex vivo reusable antiviral agents.

We report the design of antimicrobial nanocomposite films based on conjugates of multiwalled carbon nanotubes (MWNT) and protoporphyrin IX (PPIX) that are highly effective against Staphylococcus aureus (S. aureus) upon irradiation with visible light. S. aureus infections can lead to life-threatening situations, especially when caused by antibiotic-resistant strains. While the light-activated antimicrobial activity of porphyrins against such pathogens is wellknown, a facile way to incorporate porphyrins into coatings may lead to their more effective use. To that end, we decided to synthesize and characterize MWNT-PPIX conjugates which combine the biocidal capacity of porphyrins with the mechanical strength of MWNTs. The conjugates could effectively deactivate S. aureus cells in solution upon irradiation with visible light. We also designed large area nanocomposite films comprised of the MWNT-PPIX conjugates that showed potent antimicrobial activity. These MWNT-PPIX conjugates represent a facile strategy for the design of antimicrobial and antifouling coatings.

A series of mononuclear titanium­(IV) complexes with the general composition κ3-[R­{NHPh2P­(X)}2Ti­(NMe2)2] [R = C6H4, X = Se (3b); R = trans-C6H10, X = S (4a), Se (4b)] and [{κ2-N­(PPh2Se)2}2Ti­(NMe2)2] (6b) and two dinuclear titanium­(IV) complexes, [C6H4{(NPh2PS)­(N)}­Ti­(NMe2)]2 (3c) and [{κ2-N­(PPh2Se)}­Ti­(NMe2)2]2 (6c), are reported. Dinuclear titanium­(IV) complex 6c acts as an efficient catalyst for the chemoselective addition of an E–H bond (E = N, O, S, P, C) to heterocumulenes under mild conditions. The catalytic addition of aliphatic and aromatic amines, alcohol, thiol, phosphine oxide, and acetylene to the carbodiimides afforded the corresponding hydroelemented products in high yield at mild conditions with a broader substrate scope. The catalytic efficiency of the dinuclear complex depends on the cooperative effect of the TiIV ions, the systematic variation of the intermetallic distance, and the ligand’s steric properties of the complex, which enhances the reaction rate. Most interestingly, this is the first example of catalytic insertion of various E–H bonds into the carbodiimides using a single-site catalyst because only the titanium-mediated insertion of E–H into a CN unsaturated bond is reported to date. The amine and alcohol insertion reaction with the carbodiimides showed first-order kinetics with respect to the titanium­(IV) catalyst as well as substrates. A most plausible mechanism for hydroelementation reaction is also proposed, based on the spectroscopic data of the controlled reaction, a time-course study, and the Hammett plot.

Aim: The objective of this study was to develop porphyrin-based formulations to inactivate Bacillus spores. We probed the effect of porphyrins alone and in combination with germinants against both Bacillus cereus and Bacillus anthracis spores in the presence of light.Methods and Results: We tested the effect of two different porphyrins, aminemodified protoporphyrin IX (PPIX) and meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP). Treatment with the porphyrins alone did not significantly influence spore viability. However, when spores were pretreated with a solution containing the germinants, L-alanine and inosine, the spore viability dropped by as much as 4Á5 logs in the presence of light. The extent of inactivation depended on the germination conditions and the type of porphyrin used, with TMP being more effective. Conclusion: Porphyrins can be used effectively in combination with germinants to inactivate Bacillus spores. Significance and Impact of the Study: The results of this study provide evidence that porphyrins can be used to inactivate Bacillus spores in the presence of germinants and light irradiation. This finding may be general and may be extended to spores of other pathogens.