Method of delivering material or stimulus to a biological subject

Abstract

A device for delivery of material or stimulus to targets within a body to produce a desired response, the targets being at least one of cells of interest, cell organelles of interest and cell nuclei of interest. The device includes a number of projections for penetrating a body surface, with the number of projections being selected to produce a desired response, and the number being at least 500. A spacing between projections is also at least partially determined based on an arrangement of the targets within the body.

1 .- 45 . (canceled) 
     
     
         46 . A method of designing a microprojection array targeting a particular target in a subject's skin comprising microprojections having a targeting section and a support section comprising:
 selecting a target below the surface of the skin in a layer of the skin wherein the skin layer has an upper portion and a lower portion;   selecting a diameter of the targeting section to be smaller than the diameter of the target;   selecting a microprojection length based on the target depth below the skin such that the microprojection penetrates the upper portion of the layer but does not exceed the lower portion of the layer;   determining the likelihood of a single targeting event;   determining the number of targeting events required for a desired effect;   determining the number of microprojections;   determining the spacing between microprojections based on the target diameter and target spacing; and   combining the information to design a microprojection array targeting a particular target in a subject's skin.   
     
     
         47 . The method of  claim 46  wherein the target is Langerhans cells. 
     
     
         48 . The method of  claim 47  wherein the desired effect is an immunological response in the subject 
     
     
         49 . The method of  claim 48  wherein the length of the support section is:
   ( D   c   +h   layer /2)≥a≥(D c   −h   layer /2)
 
 where: 
 D c  is the depth of the target layer; 
 h layer  is the height of the layer in the skin; and, 
 a is the length of the support section. 
 
     
     
         50 . The method of  claim 49  wherein the length of the targeting section is l≥h layer . 
     
     
         51 . The method of  claim 49  wherein the likelihood of a single target event is determined by: 
       
         
           
             
               
                 P 
                 depth 
               
               = 
               
                 
                   
                     ∫ 
                     
                       a 
                       - 
                       Qσ 
                     
                   
                   
                     l 
                     + 
                     a 
                     - 
                     Qσ 
                   
                 
                 ⁢ 
                 
                   
                     dx 
                     
                       σ 
                       ⁢ 
                       
                         
                           2 
                           ⁢ 
                           π 
                         
                       
                     
                   
                   ⁢ 
                   
                     e 
                     
                       - 
                       
                         
                           ( 
                           
                             
                               x 
                               - 
                               
                                 D 
                                 c 
                               
                             
                             σ 
                           
                           ) 
                         
                         
                           - 
                           2 
                         
                       
                     
                   
                 
               
             
           
         
         where: 
         σ is the standard deviation from a mean location, accounting for the skin surface undulations. 
         D c  is a distance of the cells of interest below a surface of the body against which the device is to be applied in use; 
         Q is a number of standard deviations from a mean level of the surface of the body at which the device comes to rest in use; 
         a is the length of the support section; and, 
         l is the length of the targeting section. 
       
     
     
         52 . The method of  claim 51  wherein the spacing between the microprojections is less than or equal to the diameter of the target.