Porphyrins as Colorimetric and Photometric Biosensors in Modern Bioanalytical Systems

Abstract

Advances in porphyrin chemistry have provided novel materials and exciting technologies for bioanalysis such as colorimetric sensor array (CSA), photo-electrochemical (PEC) biosensing, and nanocomposites as peroxidase mimetics for glucose detection. This review highlights selected recent advances in the construction of supramolecular assemblies based on the porphyrin macrocycle that provide recognition of various biologically important entities through the unique porphyrin properties associated with colorimetry, spectrophotometry, and photo-electrochemistry.

Keywords: Biorecognition; biosensing; colorimetry; detection; porphyrin.

Figure 1

Schematic design of two commonly used organic frame‐based sensing platforms.20 a) Recognition and reporter units separated by a linker, e. g., Cd²⁺ binding reported by Lv et al. to the periphery of H₂‐7 26 b) Recognition and reporter function as one unit, e. g., free‐base porphyrin o‐H₂OET_NH2PP binding pyrophosphate in its inner core reported by Norvaiša et al,33 or metalloporphyrin Ni^IITPP(CN)₄ coordinating CN^‐ anions to a metal center reported by Kumar et al.28b

Figure 2

Illustration of porphyrins discussed in this review. The M in the porphyrin core represents a coordinating metal ion, its valency (n+) and axial ligands (if any) or the free base form (M=2H).

Figure 3

Schematic representation of fluoride sensing reported by Swamy et al.30 Binding of the analyte disrupts electronic communication linked between donor and acceptor resulting in an altered fluorogenic response.

Figure 4

Schematic diagram of a CSA device. Pixel by pixel, the imaging device captures pictures of well‐lighted CSA before and after exposure to the analyte. Later, the computer renders a difference map highlighting the areas of changes in color. This reflects the analyte interacting with the corresponding receptors.

Figure 5

Determination of core interactions through UV‐vis titration.33 o‐H₂OET_NH2PP interacting with pyrophosphate (PP_i) under acidic conditions

Figure 6

Schematic representation of “Tweezer‐like” porphyrin dimers.

Figure 7

Schematic illustration of a PEC biosensor.

Figure 8

General schematic illustration of a colorimetric sensor for glucose detection with a glucose oxidase (GOx)‐ and porphyrin nanocomposites‐catalyzed reaction.105

Figure 9

AP site interactions of dsDNA and H₂T(OH)₃PP: fluorescence changes are induced upon interaction with cytosine (“on”) and other nucleobases (“off”), respectively.153

Figure 10

G‐quartets stabilized by Hoogsteen hydrogen bonding and cations between two G‐quartets.