Anti-microbial photodynamic therapy

Abstract

Antimicrobial molecular conjugates for the treatment and prevention of infectious diseases caused by pathogenic microorganisms in human and animals are provided. The key to these conjugates is a special spacer connecting at least one photosensitizer to a microorganism receptor (vector) which in turn binds selectively to the surface of a microorganism bringing about photo-destruction upon irradiation. Spacers having hydrophilic structure such as ethylene glycol units and amino carboxyl end capped ethylene glycol units must be used for linking the vector to the photosensitizer. In a preferred embodiment a spacer would have at least 3 ethylene glycol units and be end capped with a carboxyl group on one end and a amino group at the other end. The present invention effectively works to combat bacterial infection in the real patient-related environments where blood, serum and other body fluids are always present or at least nearby of selected length and structure, in preferred embodiments, are used for linking the vector to the photosensitizer. These conjugate are found to be very effective in combating bacterial infection in the real patient-related environments where blood, serum and other body fluids are always present or a least nearby. A method of use is also provided.

1 . A molecular conjugate for eliminating microorganisms in real patient-related environments comprising:
 a hydrophobic porphyrin-based photosensitizer;   a hydrophilic spacer;   a targeting vector;   wherein said conjugate is capable of destroying both Gram-negative and Gram-positive microorganisms upon irradiation; and,   wherein said hydrophilic spacer has a skeletal chain made up of C, O, and N.   
   
   
       2 . The molecular conjugate according to  claim 1 , wherein said spacer has at least two ethylene glycol units and is end capped by amino and carboxyl functional groups. 
   
   
       3 . The molecular conjugate according to  claim 1 , wherein said skeletal chain of said spacer is no longer than 45 atoms. 
   
   
       4 . The molecular conjugate according to  claim 1 , which is effective in destroying Gram-negative and Gram-positive microorganisms in real patient environment which includes the presence of saliva, blood, serum and plasma, in any natural combination. 
   
   
       5 . A method of eliminating microorganisms in a real patient environment comprising the steps of:
 selecting a molecular conjugate, according to  claim 1 , with a vector component targeting said microorganisms to be eliminated;   introducing said vectored molecular conjugate to said patient;   allowing time for said vectored conjugate to accumulate in said targeted microorganisms; and,   irradiating said targeted microorganisms with an appropriate wavelength to activate said molecular conjugate to destroy said microorganisms.   
   
   
       6 . The method of eliminating microorganisms according to  claim 5 , wherein said hydrophilic spacer in said molecular conjugate has at least two ethylene glycol units and is end capped by amino and carboxyl functional groups. 
   
   
       7 . The method of eliminating microorganisms according to  claim 5 , wherein said skeletal chain of said hydrophilic spacer is no longer than 45 atoms.