Biomedical aspects of tattooing have been extensively discussed in literature, however pathophysiological effects of tattoo inks in the human body are still unexplored. Oxidative stress is considered responsible for the adverse effects of tattooing, however no experimental evidence for tattoo ink-related oxidative stress in the human body currently exists. The aim was to examine the effect of a blue tattoo on skin redox regulatory network (RRN) parameters in a single human subject. Skin surface oxidation-reduction potential (ORP) was analyzed with a PH60F flat probe. Interstitial and intracellular fluid enriched capillary blood from the tattoo and the control area was extracted and analyzed with I₂/KI-stabilized microORP, nitrocellulose redox permanganometry (NRP), carbonato-cobaltate (III) formation-derived H₂O₂ dissociation rate assay, 1,2,3-trihydroxybenzene autoxidation assay, thiobarbituric reactive substances (TBARS) assay and 5,5,’-dithio-bis-(2-nitrobenzoic acid) (DTNB)-based determination of free thiol content in low molecular weight and protein precipitate fractions. Surface ORP analysis revealed a greater antioxidant capacity of tattooed skin in comparison with the control (CTR). Capillary blood analysis confirmed greater reductive capacity in the tattoo sample both by microORP (-4.33mV vs CTR) and NRP (+10.8%). Hydrogen peroxide dissociation rate (+11.8%), and protein sulfhydryl content (+8.5%) were increased, and lipid peroxidation (-15%) was reduced in the tattoo sample in comparison with the CTR. In this N-of-1 study, RRN of tattooed skin was shifted towards a more reductive state with all parameters indicating reduced levels of oxidative stress in comparison with nontattooed skin. The local antioxidant effect of copper(II) phthalocyanine provides one possible explanation of the observed effects.

The dopamine and uric acid are primary products of purine metabolism and they coexist in serum and the extracellular fluid of the central nervous system. Some diseases of the human body are due to abnormal levels of uric acid and dopamine. Thus, the clinical diagnosis of some diseases needs a sensitive and simultaneous analysis of uric acid and dopamine. In this study, a novel conductive composite film containing multi-walled carbon nanotubes (MWTs) with cooper phthalocyanine attached to acrylate polymer (MWCNTs-CuMAPC-PnBA) was fabricated and dropped on a glassy carbon electrode and used for the simultaneous determination of Uric Acid (UA) and dopamine (DA). The modified glassy carbon electrode showed satisfactory electrocatalytic activity toward dopamine and uric acid. Low detection limits were achieved at 0.174 µM of DA and 6.87 µM of UA and the linear detection ranges of DA and UA are 5-200 µM and 20-250 µM respectively. The proposed sensing system based on the modified GCE offers promising results for rapid, cost-effective and selective simultaneous detection of uric acid and dopamine. Also, the complex modified electrode showed satisfactory results to detecting simultaneously UA and DA in real human samples (human Urine) via the standard addition method.

Biosensors are smart devices that convert biochemical responses to electrical signals. Designing biosensor devices with high sensitivity and selectivity is of great interest because of their wide range of functional operations. However, the major obstacles in the practical application of biosensors are their binding affinity toward biomolecules and the conversion and amplification of the interaction to various signals such as electrical, optical, gravimetric, and electrochemical signals. Additionally, enhancement of sensitivity, limit of detection, time of response, reproducibility, and stability are considerable challenges when designing an efficient biosensor. In this regard, hybrid composites have high sensitivity, selectivity, thermal stability, and tunable electrical conductivities. The integration of phthalocyanines (Pcs) with conductive materials such as carbon nanomaterials or metal nanoparticles (MNPs) improves the electrochemical response, signal amplification, and stability of biosensors. This review explores recent advancements in hybrid Pcs for biomolecule detection. Herein, we discuss the synthetic strategies, material properties, working mechanisms, and integration methods for designing electrochemical biosensors. Finally, the challenges and future directions of hybrid Pc composites for biosensor applications are discussed.

The versatility of metal complexes of corroles raised the interest in the use of these molecules as element of chemical sensors. The tuning of the macrocycle properties by synthetic modification of the different components of the corrole ring, such as functional groups, molecular skeleton, and coordinated metal, allows the creation of a vast library of corrole-based sensors. However, the scarce conductivity of most of aggregates of corroles limits the development of simple conductometric sensors and requires the use of optical or mass transducers that are rather more cumbersome and less prone to be integrated in microelectronics systems. To compensate the scarce conductivity, corroles are often used to functionalize the surface of conductive materials such as graphene oxide, carbon nanotubes, or conductive polymers. Alternatively, they can be incorporated in heterojunction devices where they are interfaced with a conductive material such as a phthalocyanine. Herewith, we introduce two heterojunction sensors made of junctions of lutetium bisphthalocyanine (LuPc2) with either 5,10,15-tris(pentafluorophenyl) corrolato Cu (1) or 5,10,15-tris(4-methoxyphenyl)corrolato Cu (2). Optical spectra show that after forming the heterojunction, corroles maintain their original structure. The conductivity of the devices reveals an energy barrier for interfacial charge transport, which is larger in the 1/LuPc2 device. The different interfacial barriers is also manifested by the opposite response respect to ammonia: with a 1/LuPc2 behaving as a n-type conductor and 2/LuPC2 as a p-type conductor. Furthermore, the sensors show a high sensitivity respect to relative humidity with a reversible and fast response in the range 30-60%.

A nanostructured electrochemical bi-sensor system for analysis of milks has been developed using the Layer by Layer technique. The non-enzymatic sensor [CHI+IL/CuPcS]2, is a layered material containing a negative film of the anionic sulfonated copper phthalocyanine (CuPcS) acting as electrocatalytic material, and a cationic layer containing a mixture of an ionic liquid (IL) (1-butyl-3-methylimidazolium tetrafluoroborate) that enhances the conductivity and chitosan (CHI) that facilitates the enzyme immobilization. The biosensor ([CHI+IL/CuPcS]2-GAO) results from the immobilization of galactose oxidase on the top of the LbL layers. FTIR, UV-vis and AFM have confirmed the proposed structure and cyclic voltammetry has demonstrated the amplification caused by the combination of materials in the film. Sensors have been combined to form an electronic tongue for milk analysis. Principal Component Analysis has revealed the ability of the sensor system to discriminate between milk samples with different lactose content. Using PLS-1 calibration models, correlations have been found between the voltammetric signals and chemical parameters measured by classical methods. PLS-1 models provide excellent correlations with lactose content. Additional information about other components such as fats, proteins and acidity can also be obtained. The method developed is simple and the short response time permits its use in assaying milk samples on-line.

In this work, we report manganese phthalocyanine (MnPc) films obtained by ultrasonic spray-pyrolysis technique at 40°C deposited on glass substrate subjected to thermal annealing at 100 °C and 120°C. The MnPc films were characterized by UV/Vis spectroscopy, Raman spectroscopy, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The absorption spectra of the MnPc films were studied in a wavelength range from 200 to 850 nm, where the characteristic bands of a metallic phthalocyanine known as B and Q bands were observed in this range of the spectrum. The optical energy band (Eg) was calculated by the Tauc equation. It was found that for these MnPc films, the Eg has the values of 4.41, 4.46 and 3.58 eV corresponding to as deposited, annealing 100°C and 120°C, respectively. The Raman spectra of the films showed their characteristic vibrational modes of the MnPc films. In X-ray diffractograms of these films, the characteristic diffraction peaks of a metallic phthalocyanine are observed, presenting a monoclinic phase. SEM images of these films were studied in cross section obtaining thicknesses of 2, 1.2 and 0.3 μm to as deposited, annealing 100°C and 120°C, successively. Also, in the SEM images of these films, both the average particle sizes ranging from 4 to 0.041 µm and the average diameter from 4.8 to 0.091 μm were obtained. The results agree with those reported in the literature for MnPc films deposited with other techniques.

Different therapeutic strategies have been investigated to target and eliminate HIV-1-infected cells by using armed antibodies specific to viral proteins, with varying degrees of success. Herein, we propose a new strategy by combining photodynamic therapy (PDT) with HIV Env-targeted immunotherapy, and refer to it as HIV photoimmunotherapy (PIT). A human anti-gp41 antibody (7B2) was conjugated to two photosensitizers with different charges through different linking strategies; “Click” conjugation by using an azide-bearing porphyrin attached via a disulfide bridge linker with a drug-to-antibody ratio (DAR) of exactly 4, and “Lysine” conjugation by using phthalocyanine IRDye 700DX dye with average DARs of 2.1, 3.0 and 4.4. These photo-immunoconjugates (PICs) were compared via biochemical and immunological characterizations regarding the dosimetry, solubility, and cell targeting. Photo-induced cytotoxicity of the PICs were compared using assays for apoptosis, reactive oxygen species (ROS), photo-cytotoxicity, and confocal microscopy. Targeted phototoxicity seems to be primarily dependent on the binding of PS-antibody to the HIV antigen on the cell membrane, whilst being independent of the PS type. This is the first report of the application of PIT for HIV immunotherapy by killing HIV Env-expressing cells.

Collagen has been accepted in drug delivery structures due to its biocompatible chemical, physicochemical and curative actions. The study aims to evaluate the effects of a bovine collagen hydrolysate (Clg) on the main photophysical and photodynamic properties of a new gallium (III) phthalocyanine (GaPc). The absorbance of GaPc and the conjugate GaPc-Clg showed a decrease of the intensive Q-band (681 nm) and a blue shift of the maximum (678 nm) with loss of UV-band (354 nm) for 40 mg/mL Clg. The fluorescence of GaPc was evaluated with strong emission peak at 694 nm (exc: 615 nm) which was lower for GaPc-Clg (691 nm). The quantum yield of 0.23 was obtained for GaPc which was reduced for GaPc-Clg (0.012). Photo- and dark cytotoxicity was studied by NRU-assay on pigmented melanoma cells (SH-4) and normal cell lines (BJ and HaCaT). The results suggested a slight reduction of cytotoxicity for the conjugate but almost double for the selectivity index (SI: 0.71 vs. 1.49 for HaCaT cells). The study showed that bovine collagen hydrolysate can lower the PDT activity of a powerful photosensitizer with phototherapeutic index: 819 to 360, but also minimized its dark toxicity as a positive effect in the photodynamic treatment.