The present project aims to contribute to a better understanding of the crystallisation of peptides and enable the development of strategies for crystallisation control on more representatives.

Peptides natural and synthetics are important biologically active compounds. The number of peptide-based drugs increases continually and one of the important points is their formulations. It is well known that crystallisation of a substance can helps preserving its stability and properties. Also, the biological effect of some drugs is related to the crystal syngony. For these and more reasons, study of the crystallisation of peptides from fundamental and practical point of view is valuable. As far, the process of crystallisation is tightly related with nucleation, our main tasks will be related with studies of nucleation and different approaches will be applied for this reason.

This project aims to find appropriate conditions for peptide crystallisation, studying the influence of some factors on the peptide crystallisation process. Crystallisation will be studied in pure or mixed organic solvents, in buffer solutions, following the influence of the pH, temperature and additives – soluble and non-soluble. Decoupling of both stages – nucleation and growth will be applied through designed pulses – thermal, concentration etc. changing appropriately supersaturation of the system. Before using peptides, for some experiments, proteins will be studied as model systems.

Specific objectives of the PhD project:

1) Design of new nucleating agents (NA);

2) Investigate the influence of NA, solvent, decoupling of nucleation and growth stages and complexes /or additives to form cocrystals/ on the crystallisation behaviour of three different peptides;

3) Solubility diagrams will be defined in relation to some of the factors: pH, type of buffer, temperature, concentrations. Results obtained will be discussed in the frame of classical nucleation theory considering also the two step mechanism of nucleation.

3) Optical microscopy, UV-Vis spectroscopy, DLS, etc. will be applied to monitor the prenucleation solution (i.e., aggregation formation), nucleation kinetics (i.e., induction time) and crystals’ properties (size, shape);

4) Optimise the experimental conditions to obtain crystals with uniform properties.

This PhD project is essentially experimental, and requires work, motivation, meticulousness and inventiveness. The strong supervision reveals the multidisciplinary aspect of the subject, thus requiring organizational skills and autonomy.

Funding will be provided by an MSCA Doctoral Networks program PROCRYSTAL, project number 101169471.

The main laboratories for thesis fulfilment are located at UCTM and in IPC-BAS Sofia (Bulgaria). Visits are planned to the team of Prof. Jerry Heng at ICL (UK), Dr. Simon Tanley DML (UK) and Dr. Clara Anduix JANSSEN (Belgium).

PROCRYSTAL project: The MSCA DN “Crystallization towards efficient and sustainable biomanufacturing” (PROCRYSTAL) vision is to establish crystallization as a simple, sustainable, cost-efficient and scalable process as alternative to current downstream processing techniques. Within this training program, 15 Doctoral candidates (DCs) are expected to go beyond current practise to respond to the near future biopharma manufacturing needs.

The PROCRYSTAL training program for the DCs has been framed with special attention to fundamental understanding of the underlying phenomena, from the molecular scale to process scale, and advanced experimental and modelling techniques specific to crystallisation technology. The doctoral candidates (DCs) will acquire a wide range of subject specific and general transferable skills, in an interdisciplinary and inter-sectoral environment and by multinational collaboration which enhances the early-career DCs long term employability and competitiveness.

Where to apply: Website: https://uctm.edu/en/

Academic Qualifications and Skills Required:

• Strong motivation to tackle challenging research problems.

• M.Sc. or equivalent in Chemistry, Chemical Engineering (or related) with strong overall marks

• Knowledge of crystallization will be regarded as a plus

• Enthusiasm for interdisciplinary research.

• Proficiency in written and spoken English is mandatory.

 ·      Information on the salary. Monthly salary: The salary to be attributed after applying the rectification coefficient is: living allowance of €1565,84/month (BGN 3062,51/month), plus mobility allowance of €600/month (BGN 1173,50/month), and family allowance of €660/month (BGN 1290,85/month) depending on the family situation on the date of hiring (these values ​​correspond to the gross value before the application of current taxes).

      The eligibility criteria 

• The candidates have to hold a 2nd level master's degree (120 ECTS + 180 ECTS in a degree) or a single cycle combining BSC/MSC programs (integrated master's degree of 300 ECTS) or an equivalent university degree (qualification of Second cycle). 

• Candidates must be at the beginning of their investigation, corresponding to early stage researcher (ESR).

• Candidates must not already hold a doctoral degree.

• Proficiency in written and spoken English is mandatory.

• Mobility Rule: Researchers can be of any nationality and are required to undertake transnational mobility. This means that researchers must not have resided in the country of their host beneficiary (Bulgaria) for more than 12 months in the past 3 years.

Non -eligible candidates will not be considered for the selection process.

·      Application documents:

1. Curriculum vitae and motivation letter;

2. Certificates of academic degrees and intermediate degrees certificates, including the academic path, indicating the name of the institution that attributes the degree, the date of completion, final grade; Copy of official certificates with discriminated curriculum units and their grades in obtaining each degree; Another document that is considered useful (e.g. supplement to the university diploma) to gauge the eligibility of the degree. The documents will be accepted in English and/or Portuguese;

3. Two reference letters;

4. Copy of the first two and last two pages of the passport or, for European citizens, of the citizen card.

 ·       Selection process will be organized in two steps

Eligible candidates will be invited to interview and the evaluation will be based on their merit (CV) and an interview

To the shortlisted candidates will be given additional task for brief description of the state of the art (2000-4000 characters) about the topic of the work plan to develop;

The successful candidate will be offered a PhD position to become part of our international team with global research links. Importantly, applicants must also meet the requirements of the Marie Skłodowska-Curie Conditions of Mobility of Researchers.

In addition, you can refer to the website of the project for more information on the project:https://procrystal.csic.es/

You can find additional information at the following address:  https://euraxess.ec.europa.eu/jobs/332398

For any further question please contact: Prof. D. Tsekova: d_tsekova@uctm.edu

Application Deadline: 30 Apr 2025 - 18:00 (Europe/Sofia)