Click chemistry Now and Then

Click chemistry "now and then" by numbers

No intention to be exclusive or "scientific", this is to perform a simple "statistical" count on click chemistry application in different areas . A "historical" view is provided by comparing two periods, 1999-2007 for "then" and 2011 ( Jan 1 - June 12) for "now". The data for the first period was from Sharpless laboratory's compilation of click chemistry (937 articles). The data for the second period was from a Chemical Abstract search (525 articles). 

Published articles titles were searched by selected key words and the counts are recorded as a simplified reflection of research intensity or trend. The format is "key word / number from 1st period / number from 2nd period.   

click /415/308
click chemistry /262/178
poly- /389/371
polymer /173/253
dendrimer /37/15
material /17/52
dye /2/6
fluorescence & fluorescent / 12/14
cyclodextrin /4/12
drug /26/21
inhibitor /34/25
enzyme /16/6
screen /9/3
combinatorial /10/1
Sharpless /105/1
Huisgen /22/3
synthesis /315/150
cycloaddition /121/24
nano /51/71
epoxide /9/0
triazole /129/47
Diels-Alder /12/2
water /34/9
ligation /21/5
conjugate /49/46
bioconjugate /16/21
oligo /26/16
DNA /24/18
protein /48/29
peptide /51/32
glyco /64/53
sugar /7/7

The first period was roughly the rising and maturation of click chemistry over a few years (937) while the second is the application of click chemistry in many fields in merely half a year (525). Although to obvious dissatisfaction of statisticians it is safe to conclude that click chemistry is much more widely used now than then.