DEVELOPMENT OF FLUORESCENT NANOSPROBES FROM CdTe QUANTUM DOTS and NANOPRISMS
SILVER FOR FINGERPRINT DETECTION
Detection; fingerprints; quantum dots; silver nanoparticles.
The present study explored the application of fluorescent nanoprobes, derived
from hydrophilic CdTe quantum dots (PQs) and silver nanoprisms (AgNPrs), in
revealing latent fingerprints (IDLs). The probes obtained were synthesized from
CdTe with two stabilizers: 3-mercaptosuccinic acid (AMS) and cysteamine (CIS).
Different materials were prepared from these PQs, as well as from probes
conjugated to lectins, such as concanavalin A. The conjugates obtained were
associated with a hydrophilic silica matrix for final use as a fluorescent powder or
in suspension (spray). The materials were characterized by infrared vibrational
spectroscopy, absorption and fluorescence spectroscopy, determination of zeta
potential and transmission and scanning electron microscopy. The PQs
presented sizes between 2.6 and 3 nm with CdTe_CIS emission at λ = 565 nm
and CdTe_AMS λ = 499 nm. The CdTe_CIS/SiO2 and CdTe_AMS/SiO2 probes,
when conjugated, showed a shift in fluorescence from yellow to green and a
reduction in intensity, especially in CdTe_AMS/SiO2. Samples with ConA and
ConA + AgNPrs also exhibited green shift and reduced fluorescence. In samples
with addition of AgNPrs, a significant decrease in fluorescence was noticed, a
phenomenon attributed to the confinement effect by AgNPrs. When marking IDL
on glass substrates, CdTe_CIS-based nanostructures demonstrated superior
performance, generating images with satisfactory contrast and fluorescence. The
CdTe/ConA probe was efficient in labeling, while the addition of AgNPrs reduced
the fluorescence. The study thus far concludes that the CdTe_CIS and
CdTe/ConA probes have potential for labeling IDLs, highlighting the need for
proportional adjustments in the nanocrystals, especially in probes with AgNPrs.
This work contributes to the understanding of the properties and applications of
these nanostructures in revealing IDLs.